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The dormouseconservation handbook

second edition

The dormouse conservation handbookSecond edition

byPaul Bright, Pat Morris and Tony Mitchell-Jones

Illustrated by Sarah Wroot

3The dormouse conservation handbook - second edition

Foreword and acknowledgements 51 Introduction: dormice and issues they raise 9

1.1 General introduction 91.2 Organisational framework and support 10

2 Introduction to dormouse ecology 112.1 Understanding dormouse habitats and ecology 112.2 Dormice in other habitats 172.3 Problems with small population size 18

3 Finding signs of dormice and monitoring numbers 213.1 Predicting the presence of dormice 213.2 Finding evidence of dormice 213.3 Dormouse surveys – good practice recommendations 273.4 Monitoring 283.5 Marking dormice and taking samples 303.6 Estimating population density 30

4 Habitat management 314.1 Managing woods for dormice 314.2 The objectives of woodland management for dormice 314.3 ‘Conservation Woodlands’ 314.4 Coppicing for dormouse conservation 344.5 Managing ‘Forestry’ woodlands where dormice are present. 354.6 Management of Plantations on Ancient Woodland Sites (PAWS) 384.7 Managing problems caused by deer and stock browsing 404.8 Squirrels 414.9 Hedges and their management 42

4.10 Support for habitat management 43

5 Development and mitigation 455.1 Legal background and licensing 455.2 When is a licence required? 455.3 Possible impacts from development 465.4 Predicting likely impacts 465.5 Roles and responsibilities 465.6 Planning mitigation and compensation 475.7 Mitigation and compensation methods 485.8 Nest boxes 525.9 Hibernating dormice 52

6 Legislation, legal status & licensing 536.1 Relevant direct legislation 536.2 Interpretation and enforcement 536.3 Exceptions and licences 546.4 Incidental protection 546.5 Planning policy 55

Contents

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7 Captive breeding and reintroduction to the wild 577.1 Captive breeding 577.2 Reintroductions and translocations 577.3 Progress so far 60

8 The National Dormouse Monitoring Programme 618.1 Monitoring Dormice at National and Regional Level 618.2 Other recording schemes 62

9 Conservation achievements and priorities 639.1 The UK Biodiversity Action Plan 639.2 Progress with the national action plan 639.3 Priorities for the next decade 64

10 Organisations & contacts 6510.1 English Nature 6510.2 The Department for Environment, Food and Rural Affairs 6510.3 Office of the Deputy Prime Minister 6510.4 Local Planning Authorities 6610.5 Developers and environmental consultants 6610.6 The Forestry Commission 6610.7 County Wildlife Trusts 6710.8 People’s Trust for Endangered Species and the Mammals Trust UK 6710.9 Local Biological Records Centres and the NBN 67

10.10 The Mammal Society 6810.11 Common Dormouse Captive Breeders Group (CDCBG) 6810.12 Other organisations 68

11 Case studies in development and forestry 6911.1 Developing National Cycle Route 45 in The Severn Valley, Shropshire 6911.2 Reconstructing a road junction 70

12 References 71

Nest box suppliers 73

Contentscontinued


Foreword and acknowledgements

The authors wish to express their gratitude to the many hundreds ofvolunteers who have helped with the study and monitoring of dormousepopulations over the past two decades. We also acknowledge thevaluable and extensive input from the Common Dormouse CaptiveBreeders Group, a number of ecological consultants, and fromrepresentatives of organisations that have been directly involved indormouse conservation, survey and mitigation work. A workshopattended by Nida Al-Fulaij, Neil Bemment, Caitriona Carlin, PaulChanin, Warren Cresswell, Fred Currie, Valerie Keeble, Roger Trout,Cathy Turtle and Michael Woods was very helpful in clarifying manyissues and identifying good practice. We are particularly grateful toRoger Trout of Forest Research for his very considerable input to thechapter on Habitat Management.

This handbook is endorsed by the Dormouse Focus Group (BAP group)as a contribution to the delivery of the Biodiversity Action Plan for thedormouse.

In October 2006, English Nature, Defra’s Rural Development Service andthe Landscape. Access and Recreation Division of the CountrysideAgency will come together to form a new agency, Natural England.Functions currently provided by RDS or English Nature, such as speciesadvice and licensing, will then be provided by the new agency.

Paul BrightPat MorrisTony Mitchell-JonesJanuary 2006

This considerably expanded second edition of the Dormouse

Conservation Handbook draws together much information on

the species that has been gathered since the first edition was

published in 1996. In particular, the introduction of a licensing

system for European protected species has highlighted the

need for guidance on mitigating the impact of development or

other operations on dormouse populations. Mitigation

studies are still developing, but we have included, wherever

possible, good practice guidance that should help determine

appropriate levels of survey and mitigation in a variety of

circumstances. Examples of successful mitigation are still

relatively rare and we would welcome further case studies as

they become available.

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Key messages� There is only one native species of

dormouse in Britain, whose basicbiology is very different from thatof ordinary ‘mice’.

� Dormice are protected by lawbecause their numbers anddistributional range have declinedby at least half during the past 100years. This decline still continuesin some regions.

� Dormice are important becausethey are a ‘flagship species’; where dormice occur, the habitat is usually very suitable for a wide range of other species too.They are also important as‘bioindicators’ as they areparticularly sensitive to habitat and population fragmentation, so their presence is an indication of habitat integrity and sustainable populations of other sensitive species.

� Dormice normally occur in highlydiverse deciduous woodland.They are also frequently found inspecies-rich hedgerows and scruband they also occur in habitats suchas gardens and conifer plantations.

� Dormice hibernate on or under theground from about October untilMarch or April. They are thusaffected by ground disturbance inwinter and early spring.

� Dormice are vulnerable towoodland and hedgerowmanagement operations. In manyareas, deer or livestock are also amajor problem, compromisingregeneration and reducing shrublayer extent and diversity.

� The potential presence of dormiceshould be considered whendevelopment, habitat managementor land-use change is planned thataffects any type of woodland,hedgerow or scrub. A surveyshould be carried out at the earliestpossible opportunity as mitigation

measures may depend on theseason and may not be easilyaccommodated into workstimetables later. As the dormouse is a European protectedspecies, a licence may be requiredto permit activities that wouldotherwise be illegal.

� English Nature strongly advisesdevelopers to seek the services of aprofessional environmentalconsultant with appropriateexperience when contemplating adevelopment proposal that mightaffect dormice, or potentialdormouse habitat.

� When considering applications for planning permission, planningauthorities should take account ofthe presence of dormice and otherprotected species. They mayrefuse applications where adevelopment will have adverseeffects on protected fauna or flora,or if a suitable survey to assess the impact of a development onprotected species has not beencarried out. Local authoritiesshould request applicants toinstigate such a survey beforedetermination rather than adding it afterwards as a condition ofapproval.

� If disturbance to dormouse habitatcannot be avoided, mitigation toreduce or compensate for thisdisturbance is likely to be acondition of planning approval andmust be proportionate to theprobable impact of thedevelopment. Similar conditionsare likely to apply to a licence.

� Mitigation and subsequentwoodland management may haveto be carefully timed to protectdormice. Restoration of habitatcontinuity is particularly importantand should sometimes include landthat lies outside the area directlyaffected by operations. Sometimesa considerable period of time may

be necessary to carry out this work,particularly where planting isrequired that may not mature forseveral years. Arranging tomonitor the effects of mitigationand woodland management ishighly desirable, and often arequirement of planning permission

� Mitigation may involve thetranslocation of dormice, but thisshould be considered a ‘last resort’option because it is disruptive tonatural populations and suitablesites for releasing animals may notbe available locally. Moreover,establishing translocated dormicepopulations is a complex andexpensive operation that requiresspecialist supervision.

� Protected species legislationapplies independently of planningpermission. Licences may benecessary for operations that do not require planning permission but do affect dormice.

� This document gives genericadvice on woodland management,the assessment of developmentimpacts and the creation ofmitigation plans. It does not give a comprehensive explanation ofcurrent legislation, and readers may wish to seek their own legal advice.


Widespread populations

Scattered populations

Inventory record

Reintroduction site

Figure 1 Dormouse distribution. Originally dormice were widespread over most of England and Wales, but they are now found only in the shaded areas. Circles show records from the national dormouse inventory, collected since 1990.Stars show sites of reintroductions carried out as part of the Biodiversity Action Plan. This map can help to predict thelikelihood of finding dormice in an area.


1 Introduction: dormice and issues they raise

entirely absent from Scotland. Themost northerly location is nearHexham in Northumberland, with atleast three more sites in Cumbria.Dormice are now either absent orvery thinly distributed in mostmidland and many southerncounties. In Wales dormice havebeen found in a few widelyseparated areas in every countyexcept Anglesey (Jermyn,Messenger & Birks 2001).Although it is still uncommon, thedormouse appears to be relativelywidespread in southern Englishcounties but, because of itsspecialised habitat requirements, it is never as numerous as woodlandrodents such as the wood mouseApodemus sylvaticus and bank voleClethrionomys glareolus. Even incounties where it is widespread, thedormouse has a very patchydistribution. It is particularlyassociated with deciduouswoodland, but also occurs widely inspecies-rich hedgerows and scruband sometimes in other woodyhabitats. The total adult populationis now thought to number about45,000 (Battersby 2005), distributedamong a variety of widelyfragmented sites.

Hazel dormice are sensitive toweather and climate, both directly and indirectly, throughtheir specialised feedingrequirements. They areparticularly affected by habitatdeterioration and fragmentationand also by inappropriate habitat

management. For these reasons,they are highly vulnerable to localextinction. They are consequentlygood bioindicators of animal andplant diversity: where dormice arepresent, so are many other lesssensitive species. The successfulmaintenance of viable dormousepopulations is a significantindicator of an integrated andwell-managed countryside. Theircontinued presence is thereforehighly desirable.

Dormice have full legalprotection, and their presencemust be taken into account whenhabitat changes are likely as aresult of development or changesin woodland management.

This publication is intended to bea practical guide for specialists.Its purpose is:

1 To provide guidance forwoodland managers and others wishing to promotedormouse conservation byactive management of suitable sites and habitats.

2 To provide guidance fordevelopers, foresters and other land managers, whoseactivities may impinge ondormouse habitats.

3 To provide a range ofspecialised references andcontact points for those who wish to know more.

The hazel dormouse is a distinctivenative British mammal that isinfrequently seen owing to its rarityand nocturnal habits. It is rarelycaught in traps or by predators suchas cats and owls, so it is easilyoverlooked even where present.Moreover, it spends most of itsactive time high off the ground andpasses at least a third of the year inprofound hibernation, again makingit unlikely to be seen by the casualobserver. Nevertheless, thedormouse is widely known from itsappealing photographs and itsoccurrence in children’s storybooks (notably Alice’s Adventuresin Wonderland). Formerly it wasalso found by woodland workersduring coppicing and hedge layingoperations, who would often takethese attractive animals home toshow to their children. Thedormouse is therefore a familiarspecies, despite being rarelyencountered in the wild. Like thedolphin, it has the advantage ofbeing an attractive animal with no‘negative’ aspects to its lifestyle.

Over the last 100 years, the hazeldormouse has declined in bothnumbers and distribution. Recentsurveys suggest that it has becomeextinct in about half its formerdistributional range, including sixcounties where it was reported to bepresent by Rope (1885). There arenow fewer than ten known sitesnorth of a line between the Wirraland the Wash (including recentreintroductions), and dormice are

1.1 General introduction

Dormice form a distinctive family of rodents (the Gliridae), which are found widely across

Europe and Africa, with one species in Japan. They are not common anywhere, and by

international agreement they are protected throughout Europe (the Japanese species has even

been designated a protected ‘National Icon’). Two species occur in Britain, the edible dormouse

Glis glis, a squirrel-sized, non-native species that has become a minor pest since its introduction

in 1902, and the hazel dormouse Muscardinus avellanarius – the subject of this manual.

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1.2 Organisationalframework and support

In the context of dormouseconservation management and the licensing of activities likely to affect this species, the keystatutory organisations are English Nature, the CountrysideCouncil for Wales (CCW), theForestry Commission, relevantsections of Defra (and the WelshAssembly Government) and LocalAuthorities, particularly theirplanning departments. However,dormice also receive considerablesupport from non-governmentalorganisations, many of which areengaged in dormouse survey,conservation and monitoringactivities. Considerable scopeexists for fruitful co-operation withthese bodies, perhaps avoidingunnecessary duplication of effortand actively advancing theconservation of dormice. Furtherdetails of organisations involved indormouse conservation are givenin Chapter 10, and details of legalprotection in Chapter 6.


In order to understand the potentialeffects of management ordevelopment work on dormice andto help plan effective managementor mitigation measures, it isessential to understand the ecologyof these animals. It is not possibleto offer ‘one size fits all’prescriptions for action in everycircumstance. Instead, byunderstanding the principlesunderlying dormouse ecology, and the reasons why they havebecome nationally rare, it shouldbe possible to adjust proposals tofit local situations. English Natureand Planning Authority staff mayalso find this approach helpful.Specialist consultants should gaindeeper insights through their ownfieldwork or by attending suitabletraining sessions (organised by The People’s Trust for EndangeredSpecies and/or The MammalSociety). However, this section isnot intended to be a comprehensivereview of dormouse biology andsources of more detailedinformation are listed in thebibliography (Chapter 12).

Only part of the 1.3 million ha ofwoodland in England and Wales iscurrently known to have dormiceand some (for example, wet carror woods at high altitude) are veryunlikely to be suitable. Coppicewoodland is generally perceived

as potentially optimal for dormicebut represents only 20,000 ha ofthe 700,000 ha of ancient or semi-ancient woodlands. Afurther 160,000 ha of ancientwoodland was converted duringthe 20th century to plantations ofconifer (50 per cent), broadleaf(28 per cent), or mixed woodland(22 per cent). Plantations that arenot recorded as ancient woodlandsites make up another 300,000 ha,and consist mostly of conifers.Dormice can inhabit Plantationson Ancient Woodland Sites(PAWS) and also new plantations,even quite small ones, especially ifthey are strongly linked to othersuitable habitat including scrub,bramble or gorse.

The dormouse is a nocturnalanimal that lives mainly indeciduous woodland and scrub,where it feeds among the branchesof trees and shrubs. Except forhibernation, it rarely descends tothe ground and is reluctant tocross open spaces, perhapsbecause of the danger posed byowls and other predators. It feedson a wide variety of arborealfoods (Richards and others 1984),including flowers (nectar andpollen), fruits (berries and nuts)and some insects (especiallyaphids and caterpillars). They willalso eat buds and young leaves,

but cannot efficiently digest largeamounts of mature leaves as theylack a caecum in their digestivesystem. In the autumn there isabundant food in the form ofberries and nuts, but these are notgenerally ripe before aboutAugust. So, in the early summer,the dormouse must move from onetree species to another as thedifferent flowers becomeavailable. When these are over,but fruits are not ready, there is aperiod of potential food shortage.At this time, insects may becomeimportant in the diet, but insects(particularly aphids andcaterpillars) are also consumed atother times. It follows that a highdegree of diversity among tree andshrub species is desirable in orderto ensure that an unbrokensequence of foods is availablethroughout the summer. Certaintree species are particularlyvaluable as providers of food atdifferent times of year (see Table1). Hazel appears to be animportant provider of insects, andits nuts form the main food usedto fatten up for hibernation.Where hazel is scarce or absentsmaller fruit seeds, such as thosefrom hornbeam or blackthornsloes (Eden & Eden 2003) maysuffice, but offer less food inexchange for the gnawing neededto open them.

2 Introduction to dormouse ecology

Although traditionally associated with hazel, dormice actually occur in a wide variety of woody

habitats, ranging from ancient semi-natural woodlands with hazel coppice and standard oaks,

to species-rich scrub. They are also increasingly reported living in hedgerows, areas of

plantation conifers and rural gardens. They may even be found occasionally in heathland Culm

grassland and other habitats where these occur close to woodland. Some of these sites may

well comprise sub-optimal habitat, with low densities of dormice present, but others often

harbour significant numbers. Their absence should not be assumed simply on the basis of a

‘non-typical’ habitat.

2.1 Understanding dormouse habitats and ecology

Hazel Where present, this is the principal source of food (nuts) for fattening up prior to hibernation. Hazel also supports many insects, including caterpillars, which are potential dormouse food. Hazel forms a continuous understorey of sprawlingpoles, easy for arboreal activity and is a very valuable (but not essential) species for the dormouse.

Oak

Honeysuckle

Bramble

Sycamore

Ash

Wayfaring tree

Yew

Hornbeam

Broom

Sallow

Birch

Sweet chestnut

Blackthorn

Hawthorn

Conifers

Other species such ascherry, crab apple, holly, ivy.

An important source of insect food (including caterpillars). Dormice also eat oakflowers, but acorns are of little value.

The plant’s finely shredded bark is the preferred nesting material used by dormice.Honeysuckle flowers also provide food at a time when few other things areavailable, with berries later. The climbing strands also offer convenient routes intothe trees and provide dense shelter in which to nest.

Its flowers and fruits are very important dormouse foods and tend to be available for a long period (especially where the site has slopes which vary the amounts ofsunlight on the shrubs) and the thorns provide good protection for nests.Bramble often flowers late, when many other species are over and dormice also eat the berries and seeds in autumn. Dormice seem to thrive where blackberries are abundant, even in the absence of hazel. Bramble is best if scattered amonghazels and trees.

A valuable source of insect food and pollen. A useful tree: dormice can survive inhabitats with many sycamores. However, sycamores cast a dense shade whichreduces the understorey. Thus sycamores should be kept few and scattered, perhapscoppiced to prevent seeding and to reduce the extent of shading.

Ripening seeds (‘keys’) are eaten whilst they are still on the tree, but ash supportsfew food insects. The canopy does not cast a dense shade, but generally ashwoodlands are not good habitat.

Fruits in late summer when little else may be available. Dormice eat the seeds andprobably also the flowers.

The fruits are a favoured food and dormice will make special excursions to reachthem, but the seeds are not eaten.

Seeds are small and hard, but dormice eat them. The advantage is that they are toosmall to be attractive to squirrels, so they may form an alternative food wheresquirrels have taken most of the hazel nuts. Fruiting is erratic.

Flowers are eaten in early summer.

Unripe seeds are eaten from the flowers in early summer. Sallow also supports manyinsects.

The catkins are over too early in the year to be much use to dormice, but they can eatthe seeds. These are too small to attract squirrels and may provide support wheresquirrels compete for hazel nuts.

Chestnuts are an excellent food source and dormice may also eat the flowers.

Fruits (kernels) are eaten but the flowers come too early in the year. Denseblackthorn thickets tend to be avoided where alternative shrubs are available.

Flowers are an important food in the spring. The fruits are eaten occasionally.

Little is known about the use made of these trees by dormice, but they often supportmany aphids and caterpillars – potential dormouse food. The trees may also provideshelter from the wind and rain in exposed sites.

Little is known about the value of these trees to dormice, but it is likely that they willeat the pollen (stamens) and perhaps fruits. Ivy is a useful source of food insects andits evergreen tangles among tree branches are often used for summer nesting sites.

Table 1 Trees and shrubs of value to dormice

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In addition to hazel, oak, brambleand honeysuckle are especiallyvaluable food sources, butdormice can survive without atleast one of them if an appropriatesubstitute is available. Most gooddormouse sites will have most ofthese species, but the absence ofany, or even all, of them is notevidence that dormice are alsoabsent. Nevertheless, theassociation between dormice andhazel is particularly strong and isrecognised by the animal’s Latinname ‘avellanarius’, which means‘hazel’. The majority of dormousesites include hazel, but this doesnot mean that dormice occur onlywhere it is present. On thecontrary, they can sometimes befound living among other woodyspecies, even conifers. They alsooccur in species-poor habitats suchas areas of secondary growthdominated by sycamore. Howeverthese sites often constitute sub-optimal conditions in which thepopulation is likely to have arrivedrelatively recently and may not besecure in the long term as thehabitat matures. The occurrenceof dormice in such sites, and evenoccasionally in gardens, shouldnot imply that these are corehabitats, nor distract from the needfor appropriate conservationmanagement elsewhere.

Dormice do not normally travelfar from their nest (usually lessthan 70 m), so the different treesand shrubs necessary to maintain asequence of foods through theseasons must be present within asmall area. This implies that avery mixed habitat is desirable.Dormice are highly arboreal, so itis also important that the animalsshould be able to move easilyfrom tree to tree without comingto the ground, and that they shouldbe able to climb between theunderstorey and canopy withoutdifficulty. A continuous shrublayer is ideal, especially wherethere are a few larger canopytrees. It is essential that the treecanopy does not cast too muchshade. Heavy shading means the

understorey will fail to fruitvigorously and may even besuppressed, reducing or removingkey sources of dormouse food.As a rule of thumb, if visibility in high summer at eye level ismore than about 20 m, the shrublayer is likely to be thinning out,and deteriorating as dormousehabitat. Conversely, the bestwoodland habitats are usually indense understorey thickets (wherevisibility is severely restricted),especially those incorporatinghazel. Dense thickets offer three-dimensional arboreal routesthrough the habitat, providingaccess to the tree canopy and avital alternative to activity on theground. Scrub and sprawlinghedgerows often meet thesecriteria and benefit from fullexposure to sunshine, maximisingpotential dormouse food and oftensupporting substantial populations.

Thus it is important that thephysical structure of the habitat isappropriate as well as providing asufficient variety of woody plantsto supply a succession of foods aseach becomes seasonallyavailable. Although tall, shadedspindly growth can sometimessupport dormice, it is a poorhabitat for them compared to anopen tree canopy over well-litdense shrubs which is ideal.The best canopy trees are oaks,with hazel and bramble providingthe best understorey so long asshading is not heavy enough tocompromise their fruiting. Radiotracking studies suggest that innorthern sites, the vegetation isless productive, forcing thedormice to enlarge their homerange in order to obtain sufficientfood. This uses up more energyand adds to the problems they facefrom inclement weather conditionsand lower ambient temperatures.

Although they may weave their ownnests (up to the size of a grapefruit)in bushes and shrubs, dormiceprefer to use more robust restingplaces such as hollow tree branches,squirrel dreys and old bird nests.


Tree hollows tend to be scarce inBritish woodlands particularly incoppice, in young plantations and in the vigorous undergrowth thatprovides the best feeding areas fordormice. Hence there is a need forolder trees and shrubs with hollowsand rotten branches to be available.Hollow tree stumps and coppicestools may also be used ashibernation sites. Nest boxes are aparticularly attractive substitute fornatural tree holes and, where boxesare provided, a high proportion ofthe dormouse population may usethem. Provision of nest boxes canincrease the local populationdensity, suggesting that theavailability of nest holes may beone of the factors that limitdormouse numbers. However, nestboxes are not normally used forhibernation.

Summer dormouse nests have alsobeen found in bat boxes and birdnest boxes. Where such boxes areprovided for the conservation ofrare bird and bat species, it wouldbe advisable to either increase thenumber of boxes to ensure thatthere is a surplus or put outdormouse nest boxes as well.

Dormice have a patchydistribution, even within the same woodland. This may beassociated with patchiness in food supplies, but might also be a result of social or territorialbehaviour. Male dormice areterritorial in the breeding period(May to September) and mayattack each other, so thepopulation tends to be spreadthinly. Even the best habitats maynot support more than about fouradult males per hectare. Femalesgive birth to (usually) four or fiveyoung, from early June untilSeptember (but mainly in July orAugust). The young remain withtheir mother for up to two months,delaying her production of asecond litter. If young are borntoo late in the summer they maybe unable to reach a viable weightof 15g by late October beforehibernation is forced upon them.

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Maintain and enhance speciesdiversity in the shrub layer.Some mature trees standamong shrubs, providing accessto the tree canopy.

Log piles providesummer and winternesting sites.

Dense regrowthof spindly treesshould bethinned toreduce shading.

Dense regrowthof spindly treesshould bethinned toreduce shading.

Corridor of trees and uncut shrubs

links coppice blocks.

Areas of maturecoppice, ideally12-20 years old.

Coppiced sycamore provides abundant insect food without scattering seeds everywhere.

Dead hedgingsurroundsregrowing coppicestools to protectthem from deer.

Figure 2 Features of good dormouse habitat management. The best habitat for dormice is in actively coppiced ancientwoodland that maintains a rich herb and shrub layer below an open canopy.


Honeysuckleleft in place.

Bramble regrowth providesflowers and fruit over an

extended period.

Tree branches meet at narrow pointsalong rides, allowing dormice to

cross without descending to the ground.

Ivy left on trees.

Some clusters of treeshave linked canopies.

Newly cut coppice besideestablished coppice.

Standards are generally widelyspaced to avoid shading theunderstorey.

16

It is unlikely that such smalljuveniles will survive the winter,having run out of fat reserves beforeeffective feeding becomes possibleagain in the spring. Thus, althoughsome females may breed twice in aseason, it is unlikely that they willraise more than one litter per year.The age of the young – in days –may be estimated by taking theirmean weight (up to 8 g), subtracting1 and dividing by 0.16 (see Chapter 8). Sometimes femalesmay aggregate their families into a crèche, with up to nine youngpresent at once. Individual malesmay share the same nest box withthe same female in two successiveyears, implying a long-term pairbond and perhaps more complexsocial behaviour than is normal forsmall rodents.

During the winter, when little foodis available, dormice save energy bygoing into hibernation. Havingspent all the summer in trees andshrubs, they now descend to theground and stay there all winter. A small tightly woven nest is madeand the animals usually spend thewinter there alone. They hibernateunder logs, under moss and leavesor among the dead leaves at the baseof coppice stools and thick hedges.Dormice choose a moist place tohibernate, where the temperaturewill remain cool and stable and thehumidity high. Cool conditions arevital as metabolic processes areslowed at lower temperatures andfat reserves will then last longer.Damp conditions are also necessarybecause water vapour is lost duringthe animal’s breathing. Hibernatingin a moist place will ensure theanimals do not desiccate during thewinter, as they do not wake up anddrink regularly.

Hibernation begins when thenights become cool in the autumnand there is little food left in thetrees, generally around the time ofthe first frosts. Larger dormice(weighing up to 40 g) appear toenter hibernation earlier, whilesmaller animals continue to feeduntil later in the autumn. These

may remain active until Decemberin mild years, especially in thesouth of England. Once inhibernation dormice do not usuallyleave their nests until thefollowing spring (other hibernatorssuch as bats and hedgehogs oftenmove about and feed during thewinter months). Dormice do notnormally hibernate successfully in nest boxes because thetemperature inside is too variable.

During cool or wet periods insummer, dormice may spend severalhours a day in a state of torpor. Inearly summer, more than nine hoursper day may be spent in torpor,although by autumn the averagetime is less than half an hour. Theanimals become moribund andinactive as the body cools, with theirnormal temperature (similar to our own) falling to little above thatof their surroundings. The torpidanimal is tightly rolled up with thetail curled over its belly and face.Torpor economises on energy

expenditure, but at the cost ofdelaying breeding, often until longafter other woodland mammals havealready raised young. Early in theseason, dormice may go torpid inflimsy nests, from which they areeasily dislodged by the wind. It isnot uncommon to find a torpidanimal lying on the ground in theopen, on a footpath for example. Insuch cases the animal is best movedto nearby shelter and allowed towake up and look after itself.

Dormice are highly sensitive to theweather and on cold nights willabandon their nocturnal feedingearly. A 5 °C fall in air temperaturemay result in feeding activity beingcurtailed by an hour or more. Inaddition, dormouse fur is very fineand poorly suited to throwing offwater droplets, so rain and drizzleare a danger to these animals,whereas mice and voles, with adifferent fur structure, are betteradapted to cope. In the autumn,when nights are cold (below 9 °C

Figure 3 Hibernation nest. After being arboreal all summer, dormice retreat tothe ground to hibernate. They weave a tight ball of grass or other fibrousmaterial and pass the entire winter hibernating in the same place. Hibernationsites are chosen that are cool and moist, such as under moss or leaf litter, incoppice stools or under brushwood.


at midnight), dormice will oftencompensate for reduced nocturnalactivity by coming out during theday. The unpredictable Britishclimate thus affects dormicedirectly, but it also has indirecteffects through their food supply.Warm sunshine stimulates the flowof nectar, helps to ripen fruits andspeeds the growth of insects, allproviding richer food supplies.Conversely, cool, cloudy conditionsretard the production of dormousefood. In some years the majority ofsummer days may be dominated bycool, wet ‘westerly’ weatherconditions, probably affecting theability of female dormice to raisetheir young and also reducing theviability of independent juveniles.This may limit their success,especially in northern areas at theedges of their natural distribution,on higher ground and in moreexposed sites. In such places goodhabitat management becomes evenmore important.

It is likely that a succession of badyears, with inclement weather andpoor breeding success, has created aseries of historical bottlenecks inthe dormouse population. Thiswould be particularly dangerous forsmall isolated groups of animals,whose numbers may then bereduced to a non-viable level,resulting in local extinction. This islikely to have happened more oftenin the north of England than thesouth (where weather conditions aregenerally more favourable), and it isin the north that the greatestcontraction in dormouse distributionhas occurred and where dormice arestill declining. The same principlesapply in microcosm to hilly sites.Habitats on south facing slopes arelikely to be better for dormice thanthose with a shaded, northerlyaspect. Narrow valleys, particularlywith a north-south orientation wheredaily exposure to direct sunshine isbrief, are likely to be inferiorhabitats compared to more gentleslopes. However, a varied localmicrotopography may beadvantageous because the diversityof conditions and variation in

exposure to sunshine will result inextended fruiting and floweringseasons, providing dormice withmore feeding options.

2.2 Dormice in other habitats

The best conditions for dormice areto be found in extensive ancientsemi-natural woodland, where therehas been time for shrub speciesdiversity to develop, and wherecoppicing of hazel is carried out ona long rotation. This appears toconstitute the species’ core habitat,especially where shrubs flourish inclearings and around woodlandedges. However, this does notmean that dormice occur nowhereelse, nor does it imply that otherhabitats are necessarily poor.Indeed, some types of scrub, youngplantation and hedgerow offerexcellent conditions, partly becausethey are unshaded and highlyproductive. Such sites maytemporarily even have moredormice than an equivalent area ofancient semi-natural woodland.Occasionally dormice are found ingorse scrub, heathland and even inalder trees among reeds. They havealso been found in gardens amonghoneysuckle or hibernating inclumps of pampas grass. However,these unusual occurrences shouldnot distract from focussing on whatis normal. At the same time, theexceptions indicate a need to beaware that dormice do occur in awide variety of sites and the needfor survey and consideration shouldnot be overlooked simply becausethe habitat comprises somethingother than ancient semi-naturalwoodland. Moreover, theoccurrence of dormice in ‘non-typical’ habitats may indicate thepresence of a thriving population ofthese animals in adjacent areas.

2.2.1 Scrub

In some areas dormice can be foundflourishing in scrub (Eden & Eden1999), but such habitats tend to berelatively ephemeral (beingsucceeded by high trees in time).Scrub also often develops as a

successional advance on previouslyopen ground when, for example,grazing ceases. Where such sitesare isolated by open ground, theyare less likely to become colonisedby dormice, irrespective of theirhabitat quality. Moreover, wheresuccession takes place on openground, the trees or shrubs tend tobe of similar age and grow at highdensity. For some years, this mayform good dormouse habitat, but intime, competition for light and spaceamong the shrubs and saplings oftenresults in tall, spindly growth. Afterabout 10 to 15 years, this may beginto offer poor potential for dormiceand the dense shade cast by thetaller trees may reduce the viabilityof the understorey. Nevertheless,scrub can provide excellentconditions for dormice.

2.2.2 Conifers and plantations

Despite the importance of shrubdiversity and abundant sunlight,dormice are sometimes discovered(frequently so in some areas) in therelatively uniform conditions ofplantations, particularly where theseconstitute Plantations on AncientWoodland Sites (PAWS). Surveysindicate that dormice may occur inup to 85 per cent of PAWS that have hazel present. Often thedormice occur where conifers havebeen planted into existing deciduouswoodland or scrub and they may bepersisting despite increased shadingas the conifers grow. Plantationsthat are at the scrubby pre-thicketstage or have not been ‘cleaned’(that is, broadleaves removed duringthinning) probably have a muchhigher chance of having dormousepopulations. However, some sitesappear to support dormice in thevirtual absence of deciduous treesand shrubs. It is difficult to see how they manage, but certainsoftwood species may well supportsufficient insects (aphids andcaterpillars for example) to sustain a small dormouse population in theabsence of more conventional food.It is also possible that dormice canmake use of sap as a food source insuch habitats.

It is important not to assume thatdormice will be absent fromplantations and conifer-dominatedhabitats (especially where somedeciduous species are present).Nevertheless, nationwide, theirpresence is unusual and isespecially unlikely in uplandconifer plantations. It is currentpolicy for conifers to be removedfrom many ancient woodland sitesand the possibility that dormicemay be present should not beoverlooked. Suggestions forappropriate survey andmanagement are described later.

2.2.3 Hedgerows

Dormice also live permanently insome hedgerows which provide acontinuity of foods throughout theactive season. If they areunshaded, hedgerow shrubs oftenfruit well and thus offer abundantfood for dormice. Hedges are also

important dispersal routes, a vitallifeline linking dormousepopulations in small copses. Thebest hedges are those with a highshrub diversity, a feature ofancient hedgerows, although somerecent hedges may also be verydiverse. Hedges need to be cutregularly if they are to remaintight and stock-proof, but cuttingevery year drastically reduces theavailability of flowers and fruits(for example hawthorn) that areborne on new wood. Even cuttingat 5-year intervals may removemost of the fruiting hazel.However, unmanaged hedgesbecome outgrown and oftendevelop gaps, reducing their valueas dispersal routes. Probably thebest compromise is to cut onlyshort sections of hedge at a time,or perhaps alternate sides of thehedge at 3 to 5 year intervals(though this may not be practicalin many circumstances).

2.3 Problems with smallpopulation size

Dormice live at low numbers,even in the best habitats. In early summer there are typicallyonly 3 to 5 (but sometimes up to10) adults per ha in deciduous and conifer habitats. The National Dormouse MonitoringProgramme suggests an average of between 1.75 and 2.5 adults per ha based on 83 sites in various habitats, with the lowestdensities in the north of England(1993 to 2000 inclusive; Bright & Sanderson, pers. comm.).Across the country, including sub-optimal habitats, the averagepopulation density is only about2.2 per ha. Thus small woods will contain few dormice, perhaps not enough to constitute a viable population unless the site is connected to a larger area of habitat.

18

Species Habitat Mean spring density(individuals per ha)

Source

Table 2 Small mammal population densities (pre-breeding numbers of adults per ha). Autumn densities may be severaltimes higher.

Optimal habitat (diversedeciduous woodland withabundant scrub and vigorousunderstorey)

4 to 10 adults Bright, pers. comm.DormouseMuscardinusavellanarius

Oak dominated woodland, with hazel

2 adults, increasedby 48 per cent byappropriatemanagement

Bright & Sanderson,pers. comm.

Dormouse

Scrub unknownDormouse

Conifer woodland 1 to 3 adults Trout, pers. comm.Dormouse

Hedgerow 1.3 adults Bright & MacPherson,2002

Dormouse

Deciduous woodland 40 plus Corbet & Harris, 1991Wood mouse(Apodemussylvaticus)

Woodland Up to 130 Corbet & Harris, 1991Bank vole(Clethrionomysglareolus)

Nobody knows how few is too few,but clearly a ‘population’ of lessthan about 20 animals, only half ofthem females, is very vulnerable tochance extinction as a result ofaccidents, inbreeding or poorbreeding success. Small woods ofless than 20 ha often provideexcellent habitat (because of lackof shading and large areas ofshrubby edge habitat), but if theyare not linked to other sites nearbythey probably contain too fewdormice to sustain a permanentlysecure population. Even with good

habitat, surveys show that woodssmaller than 20 ha are less likely tocontain dormice than larger sites,unless they are linked to otherareas of suitable habitat.Fragmentation of large sites istherefore damaging and it isimportant that if small patches ofwoodland are created as a result ofdevelopment projects or roadconstruction, for example, thenremnant woodlands should belinked by woodland strips orhedgerows to facilitate dispersaland effectively increase the

continuous population of dormice.Isolated woods, even quite largeones, are likely to lose their dormicein time. Species-rich hedgerowsoffer good habitat and may be anessential means of dispersalbetween woodland sites, reducingthe isolation effect of small woods,as well as providing suitablehabitat for permanent occupation.However, dormice will cross openground occasionally, so it shouldnot be assumed that small siteslack dormice simply because theyare isolated.


Table 3 Major threats to dormice.

3 Loss of woodland habitat Many areas of diverse ancient woodland have been felled andreplaced by farmland, roads and urban developments. Replantedwoodland has fewer tree and shrub species present, and thesetrees and shrubs will be of a similar age. Planted coniferssometimes support dormice.

2 Heavy shading and lack ofthinning

Canopy trees compete for the light, suppress the understorey andcreate a dark woodland with tall spindly trees and little dormousefood; generally an unsuitable habitat for dormice.

1 Decline in coppice management Ultimately results in heavy shading, suppression of regrowth anddeath of the understorey where the dormouse obtains most of its food at certain times of the year.

7 Climate change andunpredictable weather

Variable and unsuitable weather reduces breeding success andsurvival, making extinction more likely if other factors are less thanideal. This is likely to be a particularly sensitive problem innorthern counties, at sites with higher elevations and in exposedsites. Bad weather, leading to poor breeding success seriouslythreatens small isolated populations. Three bad years in a row maybe sufficient to cause local extinction. The effects of future climatechanges are difficult to predict.

6 Deer and squirrels Browsing by deer (and domestic stock) damages shrubs that providedormouse food. In extreme cases suppression of woody regenerationresults, leading to the elimination of dormice. Squirrels compete forfood, but how seriously this affects dormice is not known.

5 Loss of species-rich, infrequently-cut hedgerows

Destroys habitat suitable for permanent occupancy. Removes important food-producing dispersal corridors between woodland sites.

4 Habitat fragmentation andconsequent isolation woods

Large areas of woodland have been progressively dissected intosmaller and smaller copses, by roads and other developments.These woodland fragments often contain too few dormice to beconsidered viable populations. The remaining habitat is left inisolated blocks, often with no woodland or hedgerow connectionsthat would allow the dispersal and exchange of animals betweenlocal populations. Populations of dormice in isolated sites arelikely to suffer from inbreeding in the long term.

3.2 Finding evidence ofdormice

The presence of dormice shouldbe assumed in any areas of woodyhabitat (including plantations,hedgerow and scrub) within theirrange (see Figure 1), particularly inthe south of England.

Where development or land-usechange is proposed, only in verylimited circumstances will it beacceptable to submit mitigationplans based on little or no surveywork. An example would be wherethe habitat is both clearlyinappropriate and where thedevelopment’s impact is likely to benegligible. Surveys should normallybe undertaken to detect actualpresence or demonstrate likelyabsence. No area of woodlandshould be presumed to lack dormice,except very small unsuitable copsesof less than 10 ha in extent whichhave poor habitat and are separatedby at least 500 m from the nearest

suitable habitat. However, sincedormice are known to occur in sometypes of amenity woodland, coniferplantations and scrub, as well asdeciduous forest, the surveyprocess should not be eliminatedsolely on the grounds that thehabitat is ‘unsuitable’.

Where local surveys areundertaken in order to find newlocalities, enquiries among catowners, farm workers and throughthe local newspaper may elicituseful information. Pictures ofdormice should be used in order toavoid following up reports basedon mistaken identification. Owlpellets rarely contain dormouseremains (less than 1 per cent of allowl prey items in Britain), butskulls can be easily identified asthe teeth have distinctivetransverse ridges, not knobblysurfaces as in mice, or bold zigzagpatterns as in voles. Dormice alsohave four cheek teeth, not three asin mice and voles. Where specific

sites need to be surveyed, suitablemethods should be employed.

3.2.1 Traps and baiting points

Dormice do not normally entersmall mammal traps (for example,Longworth traps), even where theseare set in trees. American Shermantraps, baited with apple, are moresuccessful (but expensive) and wiremesh cage traps are better still(Morris & Whitbread 1986). Traps can also be made from plastic rainwater pipe (details fromthe Vincent Wildlife Trust).However, traps must be visited atleast once every day (unlike nestboxes or nest tubes). Trapping isboth time consuming and relativelyunproductive, as dormice live atlow population densities. It istherefore an inefficient survey tool and not recommended.Trapping requires a licence from the appropriate authority (English Nature or the Countryside Council for Wales).

3 Finding signs of dormice andmonitoring numbers

For sites within the distribution range of the dormouse, the only certain way of determining

their presence is by survey, using the methods described below. Dormice have been found in

small woods (even down to 2 ha where other suitable habitat is adjacent) and in woodland

traditionally considered as unsuitable, for example conifer plantations on new sites. These

populations should be encouraged, especially on the fringes of the UK dormouse range. In

some areas, dormouse survival is apparently dependent on conifers in the absence of other

woodland. Dormice could potentially occur in any woodland area, but certain factors affect

that likelihood. This simple guidance is important both for sites with primarily timber-growing

objectives (where normal cost-effective forestry operations will necessarily be carried out) and

for sites with primarily wildlife conservation objectives. In the absence of an existing survey,

a preliminary judgement based on the information in Table 4, supplemented by local

knowledge, may be made. Dormice may be found in woods with several poor characters or

are regularly moving in from an adjacent good habitat. If dormice are known to be present in

all, or part, of a contiguous habitat, they are also likely to be present in neighbouring areas of

connected woodland, scrub etc. (even where these appear to be suboptimal habitat).

3.1 Predicting the presence of dormice


22

Table 4 Factors affecting the probability of dormice being present on a woodland site within their known range. Thisincludes ancient woodland sites, Planted Ancient Woodland Sites (PAWS) and modern broadleaved or conifer plantations

Increasedprobability

Decreasedprobability

� Large woods: area over 50 ha – very likely; at least 20 ha – likely; between 2 and 20 ha –possible.

� Adjacent to ancient woodland or PAWS (including conifer), scrub or early successional stagewoodland, including conifer.

� Wide range of broadleaved species present, including some fruiting, either in patches, scatteredor at the edge.

� Wide range of ages of trees.

� Species-rich shrub layer, especially with hazel, honeysuckle or bramble.

� Species-rich edge strip or ride sides.

� Thick, wide hedgerow connections to nearby suitable woodland.

� Contains hazel or sweet chestnut coppice – ideally managed in small coupes.

� No thinning history (for conifers).

� Small wood, especially if mostly conifer.

� Old conifer plantation subject to multiple thinning.

� Isolated from other woodland or adjacent only to older conifer plantation already subjected tomultiple thinning.

� Little or no shrub understorey.

� No fruiting broadleaved trees.

� High local deer population suppressing most regeneration.

� Presence of cattle, sheep or pigs.

� Seasonally waterlogged ground.

� Derelict coppice or clear-felled in very large coupes (that is, blocks of woodland) relative to thewoodland area.

� Site more than 300m above sea level.

Figure 4 Dormouse skull and teeth. Dormice have a typical rodent skull with four molar teeth. The transverse ridges are distinctive.


Smoothed edge

Vole or mouse

Baiting points can be set up (forexample, in cardboard milk cartonsfixed to trees and supplied withpieces of apple). Dormice mayfeed here and leave distinctivedroppings which are usually largerand more crinkly than those ofother small rodents. The problemis that positive identification offaecal pellets requires experienceand is not fully reliable. Milkcartons are not very durable andthe apple bait needs frequentrenewal. This survey method isnot recommended.

3.2.2 Gnawed hazel nuts

The best way to establish dormousepresence at a site is to look forgnawed hazel nuts (see illustrationfor diagnostic features). Althoughthis is obviously impractical wherehazel is absent, it is worthsearching any adjacent areas withhazel to see if dormice are nearbyand thus likely also to be present onthe site under investigation.Several species of rodents openhazel nuts, but only the dormouseleaves a smooth round opening.Dormouse tooth marks will befound around the rim of the hole,smoothing it out, with a few toothmarks on the nut surface. There areno transverse tooth marks acrossthe rim of the nut shell. Dormousetooth marks may be visible to thenaked eye, but use of a magnifyingglass is recommended. Mice andvoles also gnaw holes in nuts, but

To conduct a systematic searchselect an area of heavily fruitinghazel and search a square ofground measuring 10 m x 10 mfor 20 minutes. If no dormousenuts are found, repeat the processin another part of the site. Thereis an 80 per cent probability that,if dormice are present, thecharacteristically gnawed nuts will be found by the time threesuch squares have been searched(Bright, Mitchell & Morris 1994).If five squares fail to yielddormouse nuts, it is about 90 per cent certain that dormice arenot present, although this is stillnot proof of absence from the site, especially in the north where dormice are particularlysparse. Heavy nut consumptionby squirrels can result in ‘falsenegatives’, so where relatively few nuts (less than 100) are found that have been opened byspecies other than squirrels – andnone have yet been found openedby dormice – it is appropriate toincrease survey effort by searching up to a further fivesquares.

An alternative way of achievingan adequate sampling intensity(W. Cresswell, pers. comm.), is to collect 100 hazel nuts that have been opened by smallrodents (voles and mice, butavoiding caches made by thesespecies and also ignoring nutsopened by squirrels). If thissample contains no nuts that have been opened by dormice it is highly probably that dormiceare not present.

Fresh hazel nuts show tooth marks much more clearly thanolder ones. It is thus best to carry out nut searches from aboutmid-August (when the nuts firstaccumulate on the ground), andpreferably before Christmas.Hazel nuts will persist on theforest floor for over a year, butgradually decay so that toothmarks become progressively lessdistinct and it is harder to decidewhich species gnawed the nut.

these are generally irregular inshape and have a different patternof surrounding tooth marks.However, most hazel nuts areopened by squirrels which shatterthem and leave a sharp, jagged andirregular opening to the nut.Squirrels will also split nuts in halfor slice off portions of the shell,leaving a large (usually oval) hole.Small round holes (only 2 mmdiameter) are the work of weevilsburrowing out. Nuthatches andother birds may peck holes in nuts,but they are irregular in shape andoften splintered at the edges, notsmooth. Where whole slices of nutshell have been removed, tiny pores(like pin pricks) are often visible inthe cut edges. This is clearevidence that the nut was notopened by the gnawing action ofsmall rodent teeth, which tends toobliterate these minute pores.

Dormice gnaw nuts up in thecanopy, dropping shells to theground below. Their nuts willtherefore tend to be scattered andmore often found below the hazelcanopy rather than close to thebase of a tree or shrub. Mice andvoles often collect nuts intocaches, dormice do not. Casualsearching for nuts is oftensufficient, but a systematic searchmakes it easier to be confident thatan absence of shells is due toabsence of the animals rather thanaccidental failure to find thecharacteristically gnawed nuts.

Dormouse

Figure 5 Gnawed hazel nuts. Dormice leave a smooth round hole with fewtoothmarks on the surface. Mice and voles may also leave a round hole, butwith transverse toothmarks on the cut edge.

24

Searches carried out after aboutEaster may need increased searcheffort to be effective, owing to theincreasing proportions of nuts inwhich the characteristic toothmarks cannot be recognised withconfidence.

Sometimes there is too littleheavily-fruiting hazel to conductthe kind of surveys describedabove In these cases it isappropriate to check otherlocations more suitable for nutsearches that are connected to the site by features along whichdormice would be expected tomove (for example, hedgerows).Should these prove to harbourdormice, then a precautionaryapproach should be taken to thesite being investigated. Thisapproach has particular meritwhen dealing with lineardevelopment schemes such aspipelines or new roads, which may affect large numbers offeatures such as hedgerows,patches of scrub and belts ofwoodland, all of which could beused by dormice and are difficultto sample by nut searches.

3.2.3 Nests

Where hazel is absent, other signsof dormice must be sought, suchas nests. Dormice may sometimesbe discovered asleep in old birdnests, tangles of ivy or masses ofconifer needles trapped amongbranches. They also weave theirown nests. Typically theseare grapefruit-size and oftenfound in brambles or otherlow-growing shrubs and aremost likely to be found inthe autumn. Dormousenests are woven fromstrips of honeysucklebark, or similar material,and frequently havewhole leavesincorporated into theouter layers. These areoften collected freshand are either green orfaded to grey. The nestsare spherical and lack an

obvious entrance hole. Thisdistinguishes them from a wren’snest or harvest mouse nest, both ofwhich have a distinct entrancehole and are normally mademainly of shredded grass. Harvestmouse nests incorporate theshredded leaves of the grass stemsto which they are attached and aretennis-ball size. Unlike dormouse

Figure 6 Summer nest. These are sometimes built in low brambles or othershrubs. They are about the size of a grapefruit, have no obvious entrance holeand usually have a covering of leaves over the woven honeysuckle core.

Figure 7 Hair tube taped to a branch. When an animalsqueezes through the baited tube it leaves hairs attachedto the sticky tape that covers the holes in the roof. One ofthese is peeled back to show the hairs attached.

nests they do not usuallyincorporate tree leaves. Searchingfor nests is time consuming andoften unsuccessful – even wheredormice are known to be present –as they mainly use other places torest (for example, tree holes) anddo not often construct nests oftheir own. Thus, failure to findwoven nests should not be used asevidence of absence.

3.2.4 Hair tubes

Hair tubes are simple to use andcheaper than nest boxes (seebelow). They can be made fromplastic sink-outlet pipeapproximately 3 to 4 cm diameter.Two 25 mm square openings mustbe cut in the 'roof' with a saw andchisel, then adhesive tapestretched across each opening withthe sticky surface facing inwards.The tubes, baited with jam orpeanut butter, are then fixed tohorizontal branches using string,cable ties or sticky tape.

As the dormice (or other smallmammals) squeeze through the


tube to get at the bait, they leavehairs stuck to the sticky tape.After a few days, the tapes can becollected. Hair samples may beacquired from mice, voles andshrews, not just dormice, and amicroscope is needed to tell themapart. This is not difficult, withpractice, and will be made easierby having comparative samplesmounted on glass microscopeslides. Dormouse hairs tend to bevery fine, much thinner than miceor voles. Under the microscopeeach hair has a ‘uniserate’ medulla(inner portion) that looks like aladder of single blocks. Shrewhairs look similar but are darkerand thicker. Mouse and vole hairshave a multiserate medulla, withseveral adjacent rows of blocks upthe middle of each hair (SeeFigure 8).

The success rate of hair tubes islow. Fewer than 10 per cent oftubes may catch dormouse hairs,even where the animal isabundant. Their advantage is thatthey may yield results within aweek, whereas nest boxes need tobe put up and left, often formonths, before they are found andused by dormice. Hair tubes arealso easier to set up among thebranches of dense shrubs andtightly trimmed hedges. They arealso cheap, so large numbers canbe put out, increasing theprobability that dormice will bedetected. Because of their lowsuccess rate, hair tubes should beused in large numbers. A densityof at least twice that for nest boxes is recommended (seebelow). Their relative inefficiency suggests that this isnot a good survey method andabsence of hairs in the tubescannot be accepted as evidencethat dormice are not present

3.2.5 Nest boxes

Wooden nest boxes, similar to bird boxes, but with the entrancehole facing the tree, are readilyused by dormice and offer ameans of detecting the animals in

the absence of gnawed hazel nuts. They are also an importantconservation tool and evidentlyboost the local dormousepopulation density (Morris andothers 1990). Those put up nearhoneysuckle are more likely to be occupied.

Although nest boxes will revealthe presence of dormice, they areoften not used immediately.Sometimes they remain empty forseveral years. Often the first signswill be nests rather than theanimals themselves. Dormousenests are woven with a ‘roof’(even inside a nest box), and theyfrequently incorporate greenleaves collected from the treecanopy above. These tend to fadeto a greyish colour as they dry out,distinctly different from darkbrown dead leaves collected fromthe ground by other species.

Figure 8 Small mammal guard hairs.Shrew hairs (top) are uniserate withdistinctly rectangular cells. The hair isblack and very fine. Dormouse hairs(centre) are also uniserate, but withmore rounded cells. The hairs are fineand sandy coloured. Mouse and volehairs (bottom) are thicker and have amultiserate medulla.

SpacingBars

Entrance

3 cm

A wire loop holdsthe box onto thetree

A wire hook onthe back of thebox holds the lidin place (not shown)

Front of roof projects forwardthe same distance as spacers

Figure 9 Nest box. Dormouse boxes are like bird boxes, but with the entrancefacing the supporting tree or branch. Spacing bars above and below theentrance allow easy access to the entrance hole, which is about 35mm indiameter. The dimensions of the box are not critical. Boxes should be attachedusing a wire sling, making it easy to take them down for inspection.

Wood mice (and yellow-neckedmice) will also make nests in theboxes, but these are not wovenand have no ‘roof’. When fresh,the nests of mice comprise a loosemass of dead brown leaves thatbecomes reduced to an untidycarpet of brown leaf fragments inthe bottom of the nest box. Birds(mostly great and blue tits) alsouse nest boxes and make a dish-like nest with no top. Their nestsare usually composed mostly ofmoss, hair and feathers, materialsthat the dormouse rarely uses.Invertebrates may use the nestboxes too, including slugs, moths,bumblebees, woodlice and,occasionally, hornets.

Nest boxes need to be used inlarge batches to be an effectivesurvey method. Fifty or moreboxes are recommended, and they should be put up in a grid, spacedabout 20 m apart. A single linealong the edge of a wood mayachieve a higher occupancy rate(due to better quality edgehabitat), but cannot give a reliablepopulation density estimate.Similarly, putting clusters ofboxes in ‘good places’ willenhance occupancy rates andincrease the probability ofdetecting the presence ofdormice, but reduce the potentialfor scientifically validcomparisons between sites.Since they are expensive, nestboxes should be consideredmainly as a means ofpopulation monitoring ratherthan as a survey tool. Furtheradvice on nest boxes canbe found in section 3.4.

Inspecting nest boxes(and nest tubes) requiresa licence from EnglishNature or the CountrysideCouncil for Wales in areas where dormice are already knownto be present. If boxes or tubesare put out speculatively to detectpresence, this in itself does notrequire a licence, but a licence isessential once the first dormousehas been found.

26

Plywood tray slides into box

Platform projects from tube

End block seals tube

Nestchamberarea

Doorstep

Figure 10 Nest tube. The tube is tied tightly to the underside of a suitablebranch with wire. The plywood tray, with attached end stop, slides into theouter tube. Tubes are readily adopted as nest sites by dormice, providing arelatively cheap and easy way of detecting their presence.

3.2.6 Nest tubes

Nest tubes are an inexpensivemeans of detecting dormice inhabitats where nut searches areunlikely to be effective. Nesttubes were first designed for use(in a larger form) with edibledormice, which found them asattractive as much more expensivewooden nest boxes (Morris &Temple 1998). Hazel dormice willreadily use a smaller version,occasionally for breeding as wellas daytime shelter. The smallertubes are made from stiff double-walled black plastic sheet, 5 x 5cm in cross section and 25 cmlong. A small plywood tray isplaced inside, projecting 5 cmbeyond the tube’s entrance toallow the animals' easy access.The opposite end of the tube issealed with a wooden blockmounted on the tray. Tubes can bemade easily but are also available

for purchase from The MammalSociety. They can be suspendedby wire or tape, fixed firmlyunderneath horizontal limbs,where they resemble a hollowbranch. The tubes can be emptiedwithout removing them by placinga plastic bag over the closed endand pushing in the wooden trayfrom the open end of the tube.This will usually dislodge anyoccupant or nest.

Being relatively inexpensive, morenest tubes can be put out thanwooden nest boxes, enhancing theprobability of detecting scarcedormice. They are also lighter tocarry and their slimmer shapemakes them easier to position indense hedgerow shrubs. Theirdisadvantage is that they probablywill not last longer than a fewyears, whereas nest boxes madefrom outdoor plywood maysurvive for a decade or more.


Being small, they are also lesssuitable than nest boxes forbreeding purposes. Nest tubesshould therefore be considered asan excellent tool for surveys, butnot for long-term populationmonitoring.

For survey work, small numbersof tubes are likely to missdormice, even where they areknown to be present. It isrecommended that at least 50tubes be used to sample a site,spaced at about 20 m intervals(Chanin & Woods 2003). Theyshould also be left in place forseveral months. Nest tubes aremost frequently occupied in Mayand August/September. Timingtheir deployment is thereforeimportant. Setting them out inApril may get early results, whilesetting them out in June may beless immediately successful. It isbest to leave them out for theentire season, from Marchonwards, for checking inNovember. In one survey in SouthWestern England sampling foronly three months (July, Augustand September) detected half thenumber of new nests and resultedin a third of the sightingscompared to a similar survey

made in a full season (Chanin &Woods 2003). See Table 5.

It is possible to set out 100 nesttubes in a single day, provided thattheir siting has been pre-determined and they do not needto be carried far. Checking shouldtake place at monthly or bi-monthly intervals, and under goodconditions 150 tubes could bechecked in one day. The tubesshould be inspected for thepresence of dormice and also forsigns of recently constructeddormouse nests. A long-handledmirror may be helpful in pricklyhedges. Numbering the tubes andsetting them out in order at regularspacing makes this survey methodmuch easier. Data recording canalso be simplified (for example, byhaving pre-prepared data sheetswith numbered grids or lines tonote the contents of each tube).

Using 50 nest tubes as a standardand Table 5 as an index of the‘value’ of different months forsurveying, a score can be devisedas an indicator of the thoroughnessof a survey. Thus, 50 tubes leftout for the whole season scores 25 (the sum of the indices for all 8 months), but 25 tubes left out in

April and May scores only 2.5 (1 + 4, divided by 2 because onlyhalf as many tubes are used).This search effort may sometimesbe enough to detect dormice, butassumed absence should not bebased on a search effort score ofless than 20. This would beobtained by using 50 tubes fromJune to November inclusive(Chanin & Woods 2003).

3.3 Dormouse surveys – goodpractice recommendations

Although it is virtually impossibleto prove that dormice are absentfrom any area of appropriatehabitat within their natural range,an adequate survey will giveconfidence that any significantpopulations have been detected.For environmental assessment ordevelopment sites, surveyproposals should be based on therecommendations in Table 6. Thefollowing is a recommendedapproach to a survey:

1 Check whether the site fallswithin or close to the knownrange of the dormouse (seeFigure 1).

2 Check for the existence ofdormouse records with the local biological records centreor on the National BiodiversityNetwork (NBN)www.searchnbn.net.

3 Check with the site owner tosee if they know whetherdormice are present.

4 If the presence of dormice ispossible, carry out a surveyusing a recommended methodat an appropriate intensity.

5 If dormice are found, submitdata to the local biologicalrecords centre.

Month Index of probability

April 1

May 4

June 2

July 2

August 5

September 7

October 2

November 2

Table 5 Index of probability of finding dormice present in nest tubes in anyone month

28

3.4 Monitoring

Nest boxes are readily used bydormice and provide the onlypractical means of monitoringdormouse populations.

A suitable nest box design is shown in Figure 9. The exact size isnot critical. The boxes are bestmade from marine ply or anotherrot-resistant wood. Make holes inthe floor of the boxes to allowdrainage. Cheaper boxes can be

made using softwoods, though thesewill often deteriorate rapidly. A lifeof three to five years is normal forcheap boxes, whereas boxes madeusing more resistant woods will lastfive to 10 years. Cheaper temporaryboxes are suitable for site surveys,but longevity is important wherepopulation monitoring is theobjective. The wood must not betreated with oily or odorouspreservatives. County WildlifeTrusts, bat groups and the RSPBmay know where to contact local

nest box manufacturers.Sponsorship may be obtained forindividual nest boxes or whole sets.Boxes can be put up at any time ofyear, but ideally should be in placeby May to allow use in the summer.In some areas, the first ones may beoccupied within a month of beingput up, in other places occupationmay not occur until the second year.If three summers pass without useby dormice, then the animals areprobably not present or the boxeshave been badly sited.

Choice

1

Method

Search for gnawedhazel nuts

Recommendations

Most efficient method. Gives quick results, but only where hazel is present.Most useful over winter. Search at least five 10 m x 10 m quadrats; more ifsquirrels have opened most of the nuts (see Section 3.2.2).

Table 6 Survey methods and good practice

Finding dormice in conifer plantations

Sites may be pure conifer or include a wide diversity of habitat, including broadleaved perimeters or mixed-speciesplantings or isolated remnants of a previous broadleaved component within, around or adjacent the plantation.

� If hazel is present it should be inspected for gnawed hazelnuts by the normal survey method.

� Within a conifer Planted Ancient Woodland Site (PAWS), locations near glades – where shrubs are associatedwith a thin canopy – or where there are contiguous broadleaved edges or internal groups are the most likelysites. Analysis of the habitat components near 1000 nest boxes (from 20 conifer sites) shows that presence ofdormice in boxes was closely related to the presence and amount of the shrub layer.

Finding evidence of dormice where no hazel exists may take months or even several years and requires theerection of nest tubes or nest boxes. To determine presence, choose the most likely locations. It may beappropriate to look where PAWS is adjacent to other suitable habitat. If dormice are found nearby in adjacentwoodland or scrub, they are likely also to be in, or at least using, the plantation. Include nearby young scrubbyplantations and other succession habitats containing bramble/gorse/bracken/old-heather and hedges.

6 Trapping Labour intensive. Needs a licence. Low ‘hit rate’. Not recommended.

5 Nest searches Not recommended as a survey method, but nests may well be found whenclearance is in progress.

4 Hair tubes Cheap; limited to summer months; requires hair identification skills. Low ‘hit rate’. Very difficult to quantify search effort. Not recommended.

3 Nest boxes As for nest tubes, but much more expensive and better suited to long-termmonitoring. Use a search effort score of 20 or more (see Section 3.2.5).

2 Nest tubes Good method, especially where hazel absent. Only useful March–November.Likely to take several months at least. Use a search effort score of 20 or more(see Section 3.2.6).


It is recommended to clean out all nests at the beginning of eachsummer. Remove bird nests assoon as the chicks have fledged to reduce the risk of infestationwith mites. Wet nests and dampmaterial from the previous yearshould also be removed as theymay harbour nematode parasitesand also hasten decay of the box.Only fresh, dry dormouse nestsshould be left in the nest boxes.Dilapidated boxes should berepaired or replaced before thedormouse season begins aboutMarch or April. It may be helpfulto mark paths with tags to makethe boxes easier to find.

When checking nest boxes, use asmall rag or plastic bag to plugthe entrance hole or cover it withone hand, then open the lidcautiously. If there is a nestinside, close the lid, lift the boxdown and open it inside a largeplastic bag. Any dormice foundshould be sexed and weighed.Unlike other small rodents,dormice rarely bite and so can behandled between palm andfingers, rather than by the scruffof the neck. Take particularcare not to handle them by thetail, as the skin is easily strippedoff and does not regrow.

For long-term monitoring, fifty ormore boxes are recommended.Where estimates of populationdensity (numbers of animals perhectare) are required, they shouldbe put up in a grid spaced about20 m apart, giving a density of 30boxes per hectare. The boxesshould be numbered sequentiallywith weatherproof ink to helplocate them and to permitaccurate record keeping.Numbering the boxes before theyare put up, then setting them outin order, is more efficient thatputting them up first then tryingto find them to number them.Putting boxes out in more-or-lessstraight lines and standardintervals also makes it easiertrying to find them again. It is agood idea to make a map,

showing where each numberedbox is located and what tree typeit is in. The most convenientheight for nest boxes is about 1.5to 2 m off the ground. Higherboxes may be more secure fromvandalism or other interference,but are no more likely to be usedby dormice.

The boxes should be sited inhazel or other shrubs and youngtrees that are linked to theadjacent understorey. Avoidisolated trees or bushes. Attacheach box to a stout branch,suspended in a loop of wire so itcan be easily lifted down andemptied into a large plastic bag.Garden wire or galvanised strandwill do, but plastic covered singlecore copper wire is best as it isslightly elastic and easier tomanipulate. Avoid having theentrance hole pointing upwards asthis allows rain to get inside. Theentrance hole should face the tree,facilitating access by dormice andmaking it more difficult forunintended occupants to enter. It does not matter which compassdirection the box faces.

Check nest boxes at least twice ayear (May and October) to recordany animals present. Howevermonthly checks will provide moreand better quality information,particularly on breeding. Studieshave shown that monthly visits do not disturb the animals unduly, but more frequent visitsare not recommended. Any new(pink) nestlings present in a nestbox should be counted and leftundisturbed. If necessary, theycan be weighed as a batch and the average nestling weightcalculated. Nestling weights can be used to estimate theirapproximate age (see Figure 12).Unlike some mammals, dormicedo not eat or desert their young,provided that disturbance is notexcessive. Nevertheless, youshould avoid disturbing youngfamilies unless detailed studiesare being made of breedingbiology.

Female

Male

Figure 11 Sexing dormice. This canbe more difficult than for othersmall rodents, particularly withyoung dormice. The difference tolook for is the distance between theanus and genital papilla(penis/vagina) which is longer inmales than females. In males, thetestes may be apparent in thebreeding season, but they are notvery prominent.

30

Inspecting nest boxes requires alicence from English Nature or theCountryside Council for Wales(CCW) where dormice are knownto be present. All data fromschemes using 50 or more nestboxes should be submitted to the National DormouseMonitoring Programme,administered by the People’s Trust for Endangered Species.

3.5 Marking dormice andtaking samples

If dormice are markedindividually, it will enable theirnumbers to be estimated moreaccurately. It will also provideinformation on how far theanimals move, which nest boxesthey use and which animals shareaccommodation. Temporarymarking will suffice for makingrough estimates of numbers, butlong-term marking is needed formore detailed studies. However,permanent marking is usuallymore expensive and intrusive sodormice should not be markedpermanently unless the intention is to continue to study them forseveral years. Marking dormicerequires a specific extension to the standard survey licence.

Dormice may be markedtemporarily by fur clipping,provided this is allowed for on the

appropriate English Nature orCCW licence. Clipped fur willoften remain visible for manymonths and does not need a HomeOffice animal experimentationlicence. Collection of bloodsamples or pieces of skin for DNAanalysis will require a licencefrom the Home Office.

More permanent marking, usingear tattoos is feasible, but requirestraining and special equipment.Toe clipping is illegal andinappropriate. Passive ImplantedTransponder (PIT) tags may beused for marking small mammals.These are tiny microchips that canbe injected under the skin andread like a supermarket bar code.PIT tags are an excellent methodof identifying an animalthroughout its lifetime. However,they are expensive (around £4 to£5 each) with electronic tag-readers costing over £100.Standard PIT tags, as used ondogs and cats, are about 13 mmlong, but are too large fordormice. A smaller, more suitablePIT tag (8 mm x 2 mm) isavailable from Pet-ID UKLimited. These tags are now usedroutinely on captive-bred dormice,with no reports of problems inanimals weighing more than 12 g.Tags can be inserted under theskin, either of the abdomen orbetween the shoulder blades, but

their use requires special trainingand must be specifically allowedfor on any licence that allows thehandling of dormice.

Taking samples of externalparasites does not need furtherlicensing, but dormice rarely carryfleas or ticks.

3.6 Estimating populationdensity

Dormouse density can beestimated using mark-recapturetechniques, normally based oncaptures in nest boxes. However,this is a time-consuming activityand unnecessary for most purposesother than research. A roughestimate of minimum pre-breedingdensity can be made by using thenumber of dormice found in boxesin May divided by the area (in ha)covered by the nest box scheme.Other survey techniques, such asnut searches or nest tubes areintended to detect the presence of dormice and do not permit anestimation of density unlessdetailed work to calibrate themethod has been carried out.For most purposes, it is adequateto use the average density figuresgiven in Table 2.

Figure 12 Predicting age from weight for babies. The age of the young in daysmay be roughly estimated by taking their mean weight (up to 8g), subtract 1and divide by 0.16.

Age(days)

1 2 3 4 5 6 7 8

Brown fur, eyes open

Weight of baby (mean for litter) (g)

Grey fur, eyes closed

Pink, no fur

0

5

10

15

20

25

30

35

40

45


There are many general actionsassociated with woodlandmanagement that would benefitdormice. The degree to whichthese are followed is influenced bywhether the site is a conservationwood managed for dormice, orwhether other objectives are ofequal or overriding importance.Definitive scientific evidenceunderpinning guidance is moreavailable for coppice woodlandthan other broadleaved woods.Research on dormice in coniferhabitats is recent and ongoing.

Whereas there are obviousconcerns about dormouseconservation in the face ofdevelopment projects (see Chapter 5), where plannedactivities directly affect dormousehabitat, it is also true that dormicecan be affected by a lack ofactivity. The reduction inwoodland management operations, particularly cessation of coppicing, resulted in extensive habitat degradationduring the 20th century. In manycases, mitigation in the face ofproposed actions is not required,because the problem is the resultof inaction, where nothing is being done at all. In these cases,restoration of derelict habitat –applying the principles outlined in this chapter – is the answer.

4.2 The objectives ofwoodland management for dormice

Dormice fare best where there is ahigh degree of species diversity

among trees and shrubs and a fullythree-dimensional physicalstructure, with plenty of linksbetween woody vegetation at alllevels. Conditions for dormicemay therefore be improved byappropriate planting, coppicing,thinning or felling.

Where dormice are alreadypresent, the aim should be tomaintain or create woodland with a high species diversity, a mosaic of age classes and a multi-storied canopy includingplenty of links between differentlevels of the canopy andundergrowth. There should also be links – via suitablehedgerows and other scrubbyhabitats – across the wholewoodland landscape. In plantedareas, especially on coniferouswoodland sites, the initial priority is the encouragement of diversity among broadleavedspecies, with a permanent increase in the shrub component.Standard uniform thinningoperations may not achieve this,so alternatives should beconsidered. In recently plantedwoodlands and where growthresults in a continuous densecanopy shading-out shrubs,keeping internal and externalconnectivity are importantpriorities. Each woodland willrequire individual managementprescriptions and plans forconserving dormice. Somegeneric management decisionprocesses may help indetermining specific needs, as shown in Figure 13.

4.3 ‘ConservationWoodlands’

4.3.1 Woods with currentlyadequate diversity and form

Good habitat for dormice is often provided by what may beconsidered young growth stands:areas of scrub, early coppiceregrowth, or young naturallyregenerated broadleaved stands.Such early successional woodland is often species-rich,though this diversity declines oncethe canopy closes and reduces thelight available to ground flora andshrubs. Soil types, exposure andrainfall strongly influence the finalstructural components of a forest but it is important tomanage the woodland to provide a range of age and tree species.The ability to manage thebrowsing impact of deer (forexample, by fencing), will often be important in deliveringsustainable young regrowthwoodland.

Management involves periodicremoval, coppicing or killing oftrees to limit the density of thecanopy layer and maintain a well-lit understorey. Felling need not be undertaken uniformly or immediately andsmall group fellings (even of trees and shrubs only three to five metres high) at intervalsthroughout the stand shouldmaintain the species richness ifundertaken every five years or so.Small groups of any species,including conifers, should be left.

4 Habitat managementWith Roger Trout, Forest Research

Sites with dormice will generally fall into two broad categories: those where wildlife

conservation is a priority for management, and those where economic forestry is the main

concern. For convenience, these types of woodland – with their differing priorities – are

referred to here as ‘Conservation Woodlands’ and ‘Forestry Woodlands’.

4.1 Managing woods for dormice

32

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Some sites may already havescattered conifers planted intootherwise deciduous habitat.Removing these may beaesthetically desirable, butindividual evergreen trees (such as

pines and spruce) may offershelter from inclement weatherand often support largepopulations of food insects, suchas aphids. Evergreens in the formof rhododendron or laurel bushesshould be removed as they offernothing useful and their spreadsmothers other shrubs. Coppicingis a desirable option, at least forsome tree species. Hand-fellingto waste may be most appropriateas the use of harvesting machineryis usually expensive and harmfulto wildlife.

Closed canopy woodland is shady and this restricts thedevelopment of small trees,seedlings and shrubs, leading tothe reduction of shrub quality and regenerative growth. Theactivity needed to enhance awoodland’s structure and itsspecies diversity will depend onthe amount of canopy shade.Shading will vary with species and density; for example larch,pine or ash allow more lightthrough to the understorey thanspruce, fir, sycamore or beech.The canopy layer should bethinned unevenly to preventcontinuous dense shade over theunderstorey and to open up glades where shrubs can develop.Where deer browsing is controlled,this management should allow avigorous understorey to develop.Some canopy trees should havetheir branches touching (to createarboreal pathways between them),but most should not. Some canopytrees in glades should be left withtheir branches touching the gladeedge to create arboreal pathways.

Where rides have been openedout to create glades (for example,for the benefit of butterflies andground flora), constrictionsshould be left every 70 m or so,where the trees meet overhead.This will enable dormice to crossthe ride without needing to cometo the ground. Where variousconservation interests need to beaccommodated a series of linkedglades is probably the best

compromise. This linking willalso provide a secluded andsupportive microenvironment for many invertebrates. Largeopen spaces and wide rides tendto alter the microclimate, increase wind speed and decrease accessibility, all negative factors for dormice and many other creatures.

Domestic stock (cattle, sheep and pigs) should be excluded from dormouse woods as theirtrampling and browsing damages the understorey. If thiscontinues unchecked, regeneration is suppressed and the wood will develop thecharacteristics of parkland –isolated trees with little or nounderstorey. This is unsuitablehabit for dormice, although theymay survive there for a while.

How shady is too shady?

The best dormouse sites have adense shrubby understorey. In this type of habitat it isdifficult to see more than two or three metres in any directionunless you are standing on afootpath. If you can see 20 m or more, this is probably becausethe understorey has thinned as aresult of shading. Such sites tendto become progressively lesssuitable for dormice.

Management of sycamore

The sycamore is a valuable treebecause it supports a highbiomass of insects (especiallyaphids), one of the best ‘value-for-effort’ foods available to thedormouse in early summer.Dormice also eat the pollen fromsycamore flowers, and probablythe ovules too. These flowers areoften available slightly later thanothers used by dormice for food.However, sycamore also casts adense shade, suppressingunderstorey development andthe flowering of many plants ofconsiderable conservation value.It is also very invasive, due to itsairborne seeds, and eliminationof sycamore is often aconservation priority.

Total eradication may not be inthe best interests of dormice, butallowing sycamore to remain risksthe loss of understorey plants. Acompromise is to pollard orcoppice the trees. They will thenproduce foliage but no seeds,and their low canopy will notresult in dense shade.


Figure 14 Ride with glades andconstrictions. Wide open rides are animpediment to dormouse movementsbecause they do not like to crossopen ground. It is better to open uprides to form sheltered glades (forbutterflies) but leave narrowconstrictions every 70m or so, wherethe trees meet overhead and allowdormice to cross without descendingto the ground.

Trees

Trees

34

1

3

6

2 8

7

4

5

1

2

3 7

6

4 8

5

Figure 15 Example coppicing scheme. Cutting adjacent coupes in successive years results in large areas of hazel less than 7years old, too young to be fruiting. It is better to cut patches in a sequence that encourages new coppice adjacent to old,permitting access to hazel crops and easy recolonisation by dormice.

✓Desirable

✗Undesirable

Trampling also endangers dormice in winter when they are hibernating on the ground.Hibernating dormice arevulnerable to predation by pigssearching for mast (acorns, nutsetc) in the leaf litter. They should always be excluded from woods where dormouseconservation is a priority.

4.4 Coppicing for dormouseconservation

Coppicing (particularly of hazel,but also sweet chestnut) helps tocreate good habitat for dormice,but management of the canopytrees is also important (see above)as coppice stools will not regrowif they are in heavy shade.Coppicing results in a renewedunderstorey, supporting plenty ofinsects and creating a vigorousnew growth of shrubs. Generally,hazel coppicing and coppicehabitats are good for dormice andthe progressive cessation ofcoppice management during the20th century was probably animportant factor in the decline ofthe species. However, coppicingmust be managed carefully or itwill speed the extinction ofdormice rather than prevent it.

4.4.1 Length of coppice rotation

Hazel and chestnut coppicingpromotes a rich ground flora andis ideal for certain species ofbutterflies. For the first two to

three years after cutting, coppiceoften develops a thick growth ofbramble between the stools.However, hazel does not usuallyfruit well before it is seven ormore years old. The ideal cyclelength for dormice is probably 15to 20 years, which is differentfrom commercial cropping andlonger than desirable for manybutterflies. After about 20 to 25years, hazel in the south ofEngland often starts to collapseand die back, although at somesites the hazel itself may still besuitable for dormice after 50 years.The management implication forsmall woods is to reduce the sizeof coupes (blocks of coppicedwoodland) and to only cut coppiceon a long cycle.

Attempting to create age diversityby cutting poles on a singlecoppice stool at different times(for example, half this year andhalf in five years time) may behelpful, but risks damage to thecoppice stool which becomessusceptible to rot and diseaseunless all the poles are cutsimultaneously.

4.4.2 Coupe size

Where deer are present, largecoupe sizes are oftenrecommended to minimise theimpact of browsing. If deer areabsent, it is better to cut onlysmall areas of hazel at a time, orcut in strips. Ideally, coppice

coupes should be small (less than0.3 ha) and in total less than 10per cent of the total woodland areain any one year. If larger blocksare cut, this may leave manycanopy trees inaccessible byarboreal routes for several years,reducing the availability ofimportant food resources todormice until the coppice hasregrown. Progressive annualcoppicing over a small isolatedwoodland site should not beundertaken otherwise too much ofthe site will be rendered unsuitablefor dormice at any one time. In asmall isolated woodland,composed entirely of coppice orcoppice with standard trees, thearea of fruiting age hazelremaining in any one year shouldnot be less than 10 ha. This canbe achieved by refraining fromcoppicing every year and/orreducing the size of the cut area.Conservation managers must alsobe prepared to reduce the densityof canopy trees above the newcoppice growth and to preventdeer or stock from browsing it.

Standards (canopy trees) should bethinned, ideally to cover 25 to 30per cent of the area. Thisrepresents about 10 large trees perhectare, perhaps more if some aregrouped together; other patchescould then have no standards at all.Standards should also be managedto diversify their age structure anddiversity should be promoted,especially retaining characteristic


species such as hawthorn, service,maple and hornbeam.Unfortunately, conservationmanagers are often reluctant tothin canopy trees, leading todeterioration of the coppiceunderneath and the creation ofeven-aged standard trees.

4.4.3 Distribution of coupes

To benefit dormice, avoidcoppicing coupes next topreviously cut areas. This willensure that new growth isalongside older shrubs, adding tothe diversity of resources. Wherecoppicing takes place in adjacentblocks in successive years, theeffect is to create a large area ofrelatively poor habitat for dormicethat will not begin to improveuntil the hazels fruit at seven yearsold. By that time the dormousepopulation might have beenreduced below a viable size.Where adjacent areas have to becut at the same time, leave uncutstrips (perhaps two coppice stoolswide) between them. These willprovide food and access routes fordormice and act as windbreaks,protecting new growth and itsassociated butterflies and otherinsects. Aim to create a verypatchy environment, with differentages and shapes of shrubs. For thefirst two to three years aftercutting, coppice often develops athick growth of bramble. This is avaluable food source, especially ifit is close to older trees andshrubs.

Extensive coppicing should not beundertaken right to the edge of awood. Leave a fringe of oldershrubs to help maintain themicroclimate within the wood.This will be beneficial toinvertebrates as well as dormice.However, this strip should not bemore than 20 m wide in order todiscourage deer from using it as alying-up base from which to raidsurrounding farmland. Edgehabitat is often excellent fordormice as it receives moresunlight than the wood’s interior.

Its management should beundertaken with care and onlysmall areas cut at a time. Do notfragment the connecting links withother woods along the woodlandmargin.

4.4.4 Timing

The optimum coppicing season for dormice is November toMarch, a period that allowsdormice to fully exploit the nutcrop before they hibernate. Earliercoppicing results in the prematureremoval of this crop and alsodisturbs late nests of young.Fortunately many woods areclosed for the shooting seasonuntil Christmas, meaningcoppicing usually starts in January.Burning or chipping material thathas just been cut in winter is not aserious threat to dormice if kept toas few locations as practicable, butbrushwood piles are best left aspotential hibernation shelters fornext year. Burning in summershould be avoided as torpiddormice may be sheltering inwood piles.

4.4.5 Restoration of derelictcoppice

From the end of the 19th century,managing deciduous woodland toproduce traditional wood products(charcoal, baskets, fencing,coppice poles etc) became steadilymore uneconomic. Large areas ofwoodland were essentiallyabandoned, to be harvested onlyfor timber at long intervals. Afterabout 20 years, un-coppiced hazelstarts to collapse, the largerindividuals progressively shadingout smaller ones. Any standardtrees will continue to grow, shadethe whole site and reduce thedensity of hazel. Many hazelpoles die back through self-shading, and become rotten.Retaining a few very old hazels(which may fruit heavily) and ascattering of hollowed-out deadwood (within which dormice canshelter) will be beneficial, butextensive areas of ‘derelict’

coppice tend to support lowernumbers of dormice.

Restoration of ancient woodlandcoppice is a long-term process(Harmer & Howe 2003) andimproving the habitat for dormicemeans thinning the canopy treesand progressively, coppicinghazel. The density of hazel stoolsmay need to be restored byplanting or layering into opensunny gaps. For layering, onelong young pole from an existingstool is bent over to ground leveland pegged in place with the tipsof its branches covered by soil.After a year or so, the branch tipswill develop roots and eventuallythe pole can be severed from theoriginal stool. This is probably amore efficient way of filling ingaps than planting afresh,although this may be necessarywhere large areas are lacking inhazel. Improving the habitat fordormice will often be aestheticallybeneficial and also result inincreased ground flora, morebutterflies and other positivedevelopments.

4.5 Managing ‘Forestry’woodlands where dormiceare present.

Many woodlands that supportdormice also have othermanagement considerations. Thisparticularly applies to PlantedAncient Woodland Sites (PAWS)where dormice have survived intothe present habitat. Dormice willalso colonise new areas ofwoodland established forcommercial or aesthetic reasons.Such areas often exhibit a lowspecies diversity, contain single-agestands and have the trees plantedvery close together. Often the lackof diversity reflects the originalplanting, but also results fromremoval of unwanted species (forexample, deliberately taking outdeciduous species from a conifercrop). However, it is possible tomanage such sites in ways thatfavour dormice, withoutcompromising other objectives.

36

Standard rack (row) creation anduniform thinning treatments areaimed primarily at enhancing thequality of the next thinning oftimber. It does not result in a thickregrowth of the shrub layer as thecanopy closes again in a very fewyears. Creating gaps in it (seebelow) is a major departure fromtraditional practice, causing

potentially conflicting managementobjectives, especially whereplantations of conifers are involved

Modern (recently planted)broadleaf, conifer or mixedwoodland at the pre-thicket stagehas a strong shrub layer. This canon occasion overwhelm the plantedtrees, but is readily used by

Good Practice: mitigation during planning and forestry management

Detailed advice may change as further evidence is obtained, but good practice for managing dormouse sites, withinthe other site objectives, aims to achieve three outcomes:

Retain connectivity, so dormice do not become isolated in small areas

� Avoid removing links along the perimeter belt of scrub, understorey or canopy trees when creating access oroperational turn-round/storage areas.

� Do not completely isolate big broadleaf trees – crescent thinning is best, especially if this allows cross-rackconnection.

� Retain or create connectivity across tracks and racks (rows) at 75 to 100 m intervals.

� Retain higher level branches crossing tracks for example, when clearing to lorry height in advance ofoperations.

� Favour retention of broadleaved species when thinning, especially the shrub layer in natural gaps etc. Pollard,rather than fell, small broadleaves if deer/rabbits are present.

� Reconstruct low level connections across racks using brash or tops, especially at perimeters or near cross tracks ifaerial linkages have been lost during operations.

� As a last resort use the mechanical loader head to gently lodge trees from three rows back to create connectingbridges across racks at around 100 m intervals following timber extraction.

Retain and improve the shrub layer growth and regeneration

� Adapt brash treatment to site conditions and redistribute to create links.

� Scallop ride edges instead of cutting straight-line clearances when ride widening, to leave selected overhangingcanopy trees that act as arboreal crossing points.

� Create glades along racks and opportunistically enlarge existing areas for regeneration.

� Consider ways to avoid the use of the same racks in subsequent thinning so as not to damage emerging shrubs.

� Do not drag felled trees along every row.

Minimise disturbance and killing of dormice during forestry operations

� Always seek to avoid large clearfells.

� Follow the timing advice given in this manual (see 4.5.3).

� Do not tidy or widen ride edges strictly parallel to the track.

� Cut the ride edges of the managed compartment in autumn to discourage hibernation there if timber has to bestacked at the ride side.

� Avoid stacking or restacking timber on roadsides between December and April (inclusive). If possible, stack logson the ride side opposite to the managed compartment.

dormice, the populationpresumably being derived from anadjacent woodland, scrub orhedgerow habitat. Research hasyet to be carried out on dormice inthis habitat, but generic advice is topreserve links with any adjoiningsuitable habitat, be sensitive at theedge of a stand, ensure piecemealthinning continues, enhance or

produce a shrubby understorey andmaintain older trees (as outlinedearlier). Maintaining or creatingconnections within the woodduring forestry operations iscritical, except when working inwinter, when re-connections mustbe made before hibernation ends.

Uniform thinning does not allowsufficient time for a diverse growthto be produced. Creating gaps forscrub growth by felling trees toproduce linked patches of clearground may be the best compromisewhere various forestry andconservation interests need to beaccommodated. This can beachieved at a small-scale (forexample, in areas of around 25m2)to create a mosaic of uneven ageover several years. Group-felling oflarge well separated areas (up to 0.3ha) within a larger block appears tobe acceptable, but has the drawbackof not fulfilling the professionalforester’s desire for promotinguniform timber growth in the uncutareas. Large-scale clearfells thatcompletely remove dormousehabitat are generally unacceptable.Historically, some very large areaswere cleared – often a strip over 200m wide along a whole valley over afew years – and dormice survived inthe remnant edge woodland, scruband wide hedges to later reinvadethe new woodland. These days,habitat isolation, fragmentation anda lack of scrubland and hedgesmean that large-scale operationswith fast modern machinery have tobe carefully planned to ensure thatadjacent areas of adequate size anddiversity are reserved to act as asource of future dormousepopulations.

4.5.1 Improving rides and edges

This habitat may be the easiest todeal with first when only limitedresources are available butmanagement must ensure that thecontinuous connection around theperimeter of an area of woodland is not broken. Consider managing the edge of the existing crop by small-scale thinning, coppicing (or

pollarding, if deer are a problem).Where rides are to be opened out to create glades for the benefit ofbutterflies and ground flora or foraesthetic reasons, a wavy scallopededge should be considered withconstrictions every 70 m or so.Trees on either side of a ride shouldmeet overhead at these constrictionsallowing dormice to cross overwithout coming to the ground.Sympathetic ride widening is part ofmany management schemesdesigned to enhance biodiversity, aswell as improve game shooting.

4.5.2 Clear felling

Clear felling has the potential toseverely affect dormice as it results

in the immediate and complete lossof resources. To encourage acontinuing population, it is best torestrict the scale of operations inany one year (for example, on asimilar scale to coppicing).

Where possible, only clearfell 0.5 to5 ha units depending on the overallsize of the woodland block. If thereis suitable habitat adjacent to thecleared area, ensure that there arelinks to it on more than one side.If large-scale operations areplanned, try to ensure that adjacentcompensatory habitat is available,creating it beforehand if necessary.Felling, during the autumn, shouldthen start in the centre of largestands and continue outwards,


Commercial hazel coppicing, energy coppice and sweetchestnut coppice

Dormice can occur in coppice other than hazel, but comparatively little isknown of their ecology in such situations. Until further research is carriedout, it is difficult to offer specific advice apart from the followingobservations

1. Nest boxes will be beneficial for the same reasons as in hazel coppice.

2. Cutting the coppice in summer will be destructive to nesting dormiceand also deprive them of food resources. November to March wouldbe better.

3. Short rotation cutting of hazel (less than 10 years) may be required for economic reasons, but is incompatible with the dormouse's needfor hazel nuts in autumn. Similarly, short rotations of sweet chestnutwill reduce food availability.

4. Large coupes will be harmful to dormice, as will cutting more than 25 per cent of a wood in one year.

5. Intensively managed coppice often develops towards a monoculture,reducing tree diversity (for example, by removal of unwanted species).This will not favour dormice.

6. Restoration of abandoned coppice, if carried out using heavymachinery, may be damaging to dormice, especially in winter whenthey are hibernating and unable to escape.

7. If they are large enough, non-intervention areas may allow dormice tosurvive. Such areas should be 10 to 20 per cent of the wood if possible.

8. Willow, alder and biomass fuel shrubs are often grown on wet groundthat is relatively unsuitable for dormice and may therefore not causeconflicts of priorities to arise.

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progressively moving the animalstowards this refuge. This will bemore successful if the refuge iswell-connected to the area to befelled rather than if the animals areforced to cross open ground. Stripsof 75 m may be removed so long asuncrushed brash rows (providingaccess links to adjacent refuges) areconstructed immediately or strips ofconnected trees are left uncut.

On some soils, clearing large areasresults in a rich growth of brambleand other shrubs, but on othersMolinia grass or bracken may takeover and it may take many yearsfor tree seedlings to becomeestablished.

4.5.3 Timing of operations

As indicated earlier, there is no‘good’ time that avoidsdisturbance to dormice altogether,which is why attention to the scaleof operations and possiblemitigation measures are soimportant. Operations should, asfar as possible, avoid periods ofthe year when dormice areparticularly vulnerable –coincidentally the main bird

breeding season. The two leastdetrimental periods for thinning inconifer woods includes August toSeptember, the end of the mainbreeding period when the firstyoung have left the nest and aremobile – but before animals needto feed-up to create their fatreserves for hibernation.Alternatively, except for large-scale operations, work could beundertaken during the hibernationperiod itself. Any dormousenestlings that are disturbed in theautumn are generally tooundeveloped to survive theoncoming winter and would belost to the population anyway.

4.6 Management ofPlantations on AncientWoodland Sites (PAWS)

During the 20th century, manyancient woodland sites wereplanted up with conifers and some may have retained theirdormice. Changes in nationalpolicies towards forestrymanagement now encouragemany of these sites to bediversified and brought back intoa condition resembling their

original state. The composition of PAWS is very variable. It isincreasingly clear that many havedormouse populations, often onsurprisingly small sites, and theseneed to be taken into accountwhen deciding on an appropriatemanagement regime. It is notknown whether dormice live only near the edge of large single-species conifer compartments, or if they also inhabit the centre of large conifer blocks.

Doing nothing is not an option,either under normal conifermanagement or for PAWSrestoration to broadleavedwoodland, because the trees and most wildlife (includingdormice) would suffer as thecanopy thickened and shrub layer declined. The timing, form and scale of management are crucial to ensure dormousesurvival. More detailed guidance is given in a Forestry Commission Information Notewhich is in preparation.

4.6.1 Normal and restorationmanagement

For all conifer PAWS, theprinciples of management andrestoration may appear similarbut in practice may vary,principally in terms of scale.Standard uniform thinningfavours the remaining crop but isless likely to result in shrub andtree regeneration than thecreation of gaps and clearings.Restoration is usually a long-termprocess requiring severalmanagement operations overmany years and there is no ‘one-size-fits-all’ option. It involvesthe re-establishment of a nativewoodland mixture by removing(over time or in one clearance)most of the introduced or exoticspecies, encouraging native plant species and enhancing any ecological processes that may have been compromised.Practical planning andmethodology used for restorationwill differ from site to site

Good practice guidance – timing of operations

Traditional broadleaved coppice management (and thinning of standards)occurs in winter.

� In conifers (and broadleaf woodlands), operations that seriouslyphysically disturb the whole canopy or forest floor such as large-scalemachine felling and thinning should take place in September andearly October when animals are mobile. In these cases mitigationmust be immediate.

� ‘Small footprint’ operations (less than 5 ha) and those involving under25 per cent of a wood containing largely suitable habitat, should takeplace between September and October or between December andMarch inclusive. This may include hand-felling and rackside timberstacking. Large machinery may be used for felling rows and small areas.

� Clearfelling large areas (for example, more than 5 ha, or over 25 percent of a wood) should be done in the autumn. Large clearfellsshould be undertaken progressively over several years. Provisionalguidance is that narrow strips may be undertaken in winter – widerstrips during autumn – when the dormice are still active and capableof redistributing themselves.


reflecting local history and needs.The complete removal of conifersthat normally occurs at theclearfelling stage may be broughtforward if dormice are absent,but the edge of the plantation (toa depth of at least 50m) should betreated sensitively if there is anydoubt.

4.6.2 Planning for managementof PAWS

Before any operations take place,a planning phase should include:

� General consideration ofpotential dormousepopulations.

� A simple site survey detailingthe current conditions,previous species planted, pasttechniques employed toestablish and to manage thecrop, such as cleaning andthinning. Soil characteristicsand the shading properties(light, moderate or severe) ofthe existing tree canopy shouldalso be investigated. Thepresence, or not, of grazing orbrowsing mammals should beestablished.

� Identification of the likelyrestored woodland type.For example, the silviculturalregime that will be requiredaccording to site conditions,other local woods or nationaladvisory systems.

� The listing of other objectives, opportunities,constraints, practicalmanagement, economic and landscape issues.

This will indicate the site potentialand the nature of any restorationwork (Thompson and others 2003).

Many PAWS woodland blocks are large and contain a range ofadjoining stands often of differingspecies or ages in which dormicemight live. Boundary belts, buffer zones and the timing of

specific silvicultural works canvary across the different coupes within the wood, depending on the individual outcomes of theplanning process. AlternativelyPAWS may be a small component of the woodland area.Management and mitigation canthus be tailored to be sympatheticto dormice at the larger scale.

Whilst gradual restoration is the norm, there are importantexceptions, such as areas of potential windblow or difficultaccess. Particular difficulties areassociated with areas withdominant reseeding coniferspecies such as hemlock, or where the crop is at the finalfelling stage. Here, a more drastic single managementoperation may be necessary. Inthese situations advice should besought from the ForestryCommission or English Nature.

4.6.3 Management operations:thinning and clear-felling PAWS

The management and mitigationof typical woodland operations inthe presence of dormice has beenreferred to earlier and onlyadditional information is providedbelow. Clear-felling in conifer

PAWS has the potential toseverely affect any dormicepresent. Felling all conifersadjacent to, or in, a broadleavedwood or coppice may suddenlyremove a desirable seasonalresource such as food or nestinghabitat. Large-scale removal in a plantation results in thetemporary loss of resourceswithin an already poor habitat.Either may reduce the dormousepopulation. The main way toensure dormouse survival is torestrict the scale of operations inany one year to a scale similar tohazel coppicing, or to relativelynarrow strips within a largerrefuge habitat. Where possible,ensure that compensatory habitatis created (preferably during theplanning phase) to ensure arefuge will be available.

For the final clearance of largeareas, work should proceed overseveral years. First the centre ofthe block (around 5 ha) should becleared, then the perimeter pushedback annually in a comb- orwedge-like pattern towards apreviously prepared refuge habitat.Uncrushed brash strips should linkthe cut and uncut areas to providesheltered access routes fordormice and other wildlife.

Good practice in relation to the management of PAWS

� Preferably create small glades, group fells and open rides whilstensuring connectivity across and around the perimeter of the block.

� Use a patchwork approach, similar to the cycle of coppicing within awood.

� Leave large and, where possible, small broadleaves and link these tounfelled areas.

� Leave any broadleaved habitat strips around the margins of coniferplantations and improve habitat connectivity.

� If occasional cross rack connections are not present, lodge trees fromthree rows back across the rack during the last extraction passage orensure brash or tops are placed as wildlife access corridors at intervalsof around 100 m.

� Consider enrichment by planting with native species used by dormice.

4.7 Managing problemscaused by deer and stockbrowsing

Browsing suppresses regenerationand prevents the fruiting andflowering of shrubs. It is normally highly unsatisfactory for many reasons, not justdormouse conservation.Domestic stock (pigs, sheep andcattle) should always be excludedfrom woods that support dormice,particularly in winter.

Evidence of browsers can be seenin tightly nibbled twigs andcoppice stools, small piles ofspherical or oval black droppingsand cloven-hoofed footprints inmud. In the absence of domesticstock, deer are likely to be themain animals involved and theyare a widespread and increasingproblem in woodlands throughoutEngland and Wales. Where theyoccur in substantial numbers, thewoodland floor may becomedevoid of many species and havefew regenerating seedlings (ornone at all). Often there is a lower‘browse line’ visible on the treesin summer and the site begins tolook open as the understorey isprogressively removed orsuppressed. Deer should be takeninto account when planningwoodland management as theymay well prejudice the entirefuture woodland structure andcomposition. Fallow deer are aparticular problem as they usuallyoccur in groups, increasing theirimpact on small areas. Roe andmuntjac deer tend to be moreterritorial, usually occurring asindividuals or small familygroups.

When patches of hazel are cut, theregrowth will be very attractive todeer. Their browsing may thenseverely retard growth of the hazelstools. Scattered coppicing mayreduce this effect and will alsocreate a better mosaic habitat fordormice. Cutting very largepatches is said to reduce deerdamage, but may eventually

attract more of them! Also, largecut patches are unsuitable fordormice until the hazel hasmatured sufficiently to producenuts.

If left unmanaged, deer willdestroy large areas of understorey,reducing the food supplies fordormice, their nesting areas andtheir arboreal pathways. Habitatrestoration may then take a longtime, during which dormice coulddecline to extinction.

Three ways to prevent damageby deer:

1 Protecting individual shrubs orcoppice stools

Individual tree guards, temporaryfencing (plastic or light metalmesh or chestnut paling) or thepermanent metal-mesh fencing ofsmall areas or coupes may beappropriate. Some fence designscan be moved to another locationlater (Trout & Pepper 2005).

Fencing entire woods is standardpractice against stock and anoption against deer. It is also theeasiest way to protect the shrubsand ground flora. ‘Dead hedges'can be used to exclude deer byfencing off individual stools orgroups of stools behind a wall ofdead branches. Material cut whenstools are coppiced can be used toform these barriers. This option ischeaper than buying fencing, butis very labour intensive and oftennot fully effective. Welded,galvanised metal fencing is nowoften used to exclude people frombuilding sites, and similar panelsmay be installed in woodlandareas to exclude deer. Thisfencing is highly effective, butunsightly and costly. Metalfencing lasts well and can bemoved to another area as oldergrowth becomes less vulnerable todeer. Chestnut paling can also beused to exclude deer from newlycoppiced areas, but will probablybe useful for only one cycle ofcoppicing, becoming too rotten to

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Figure 16 Pollarded hazel. The poles are cut about 1.5m above the ground sothat regrowth is out of reach of muntjac and perhaps other deer, which nibbleoff shoots as fast as they appear. Pollarded hazel grows quickly and may fruitearlier than conventional coppice.


move after about 5 years inposition. Further suggestions fortemporary and reusable fencingare given by Pepper (1999).

2 Pollarding instead of coppicing

Hazels can be pollarded about1.5m above the ground, so thatregrowth is mostly out of reach ofdeer (and rabbits). Pollardingresults in shorter coppice poles,but this does not matter where thepoles are not being harvestedcommercially. Pollarded hazelsseem to fruit again sooner thanthose stools coppiced at groundlevel, helping to reduce the periodwhen the cut hazels are providinglittle or no food for dormice.However, pollarding requiresawkward and potentiallydangerous actions at shoulderheight using a chain saw or axe.Pollarded hazels also regrow intoa form different from traditionalcoppice stools. This may beundesirable for aesthetic reasons,particularly in woods wherepublic access and scenicconsiderations are paramount,although pollarding was acommon and sustainablecomponent of woodlandmanagement for many centuries.Pollarding hardwood trees up to40 cm in diameter is oftensuccessful, except for beech andbirch. Further advice can befound in Read (2000).

3 Deer culling

Deer numbers can be controlledby trained stalkers. Once theirimpact has been brought down toan acceptable level, deermanagement must be maintainedto keep populations at a suitabledensity (typically under five per100 ha). This is most effective ifadjacent landowners plan deermanagement together, perhaps byforming a Deer ManagementGroup. For advice and supportcontact The Deer Initiative, POBox 2196, Wrexham, LL14 6YH.Tel: 0870 774 3677;[email protected];www.thedeerinitiative.co.uk .

4.8 Squirrels

Squirrels compete with dormicefor food supplies, especially hazelnuts. Evidence for this is providedby the Great Nut Hunt of 1993(Bright, Morris & Mitchell-Jones1996), in which over 170,000gnawed hazel nuts were examined.The majority (about 90 per cent)were discarded in the field ashaving been eaten by squirrels, but13,171 were submitted for furtherchecking in the belief that they hadbeen opened by dormice. Eventhese were, in fact, mostly also thework of squirrels (see Table 7).Grey squirrels are a particularproblem because they commonlylive at more than twice the

Number of nuts per cent

8,323Opened by squirrel (and possibly some birds) 63.2

1,352Opened by dormouse 10.3

1,190Opened by wood mouse 9.0

1,091Opened by bank vole 8.3

1,215Unidentified, but not opened by dormouse 9.2

13,171Total number submitted as ‘dormouse nuts’ 100.0

Table 7 Nuts identified by the public during the Great Nut Hunt of 1993 as having been gnawed by dormice. Of the 13,000 nuts submitted as opened by dormice, more than half had actually been opened by squirrels.

population density of red squirrels,meaning that they eat more thantwice as much potential dormousefood. Moreover, a squirrel may eatseveral nuts at a sitting, each one ofwhich may represent a whole mealfor a dormouse.

Removing squirrels may bedesirable, but is probably not a cost-effective way of assisting dormice.However, in many areas squirrelcontrol is already undertaken forother reasons. Where squirrels areshot or trapped, there is no hazard todormice. Use of Warfarin-dispensing hoppers is now awidespread method of poisoninggrey squirrels. However, althoughthe hoppers are supposed to excludenon-target species, spillage of bait iscommon. This is unlikely to affectdormice as they do not normally eatwheat baits (as used in hoppers),cross open spaces, or feed on theground. Hoppers should beinspected regularly to clear up anyspillage but if they are properlysupervised and placed near theground, in open clearings, the risk todormice is minimised.Nevertheless, once poison is put out,it is difficult to control what eats it.

Red squirrels also compete foressential dormouse foods but theyare now rare or extinct over most ofthe range of the dormouse. Use ofWarfarin dispensers is illegal inareas where red squirrels occur.

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Hedgerow management good practice, for the benefit of dormice and hedgerow biodiversity

1 Except where road safety or access preclude it, hedgerows should be trimmed only every 3 years (or lessfrequently if possible) and maintained at a height of at least 3, and preferably 4, metres.

2 Ideally, about one third of hedgerows on a farm should be left to grow for 7 to 10 years.

3 It is important not to cut all hedgerows on a farm at once, so that some heavily fruiting hedgerows are alwayspresent. As a guide, we suggest cutting only 10 to 30 per cent in any one year.

4 In some places it may be feasible to cut only one side of the hedge, cutting the other a year or two later, thus notremoving all the food sources at once and allowing some regrowth before further cutting takes place. If possible,flails should not be used to manage hedgerows.

5 Coppicing or, even better, laying should be used to manage hedgerows that become gappy or lack densebranches at their base. Fencing may be needed to prevent stock from causing damage before new growth hasbecome established.

6 If hedgerow size needs to be reduced it is better to avoid cutting the top and to cut one side only.

7 When creating new hedgerows, or plugging gaps in existing ones, at least five and preferably seven differentshrub/tree species should be planted. The best species to plant are hawthorn (for its flowers and berries) andhazel (nuts and insects); with a diversity of other species to offer flowers insects and fruits at different times(see Table 1). Bramble would make a valuable addition, but may arrive naturally.

8 Where new roads or other developments cut across hedges, the ‘loose ends’ should be linked up by suitableplantings. Mixtures of hawthorn and hazel are the preferred species where early results are needed.

9 Environmental Stewardship (in Wales, Tir Gofal) will support many of these measures (see below).

4.9 Hedges and theirmanagement

4.9.1 The importance ofhedgerows

Hedgerows are of key importancefor conservation in agriculturallandscapes, both as habitat and asdispersal routes between patches ofwoodland. It is essential thathedgerow connections aremaintained between dormouse sites,especially small ones, to allowexchange of animals between siteswhich ensures genetic mixing andavoids inbreeding. However, overthe past 50 years, many hedgeshave been removed in pursuit ofgreater farming efficiency,especially in arable areas. Inaddition, changes in themanagement of hedgerows in thelast few decades have had aprofound negative impact ondormice. A survey in 2000 to 2001of 59 hedgerow sites where dormicewere present in the late 1970s foundthem absent from 64 per cent ofsites, equivalent to a 70 per centdecrease over 25 years. Hedgerowmanagement is now much more

uniform and intensive (nearly allhedges on a farm are usually cutevery year) and hand-trimming andlaying has been replaced by the useof mechanical flails and cutters.Many of these intensively-managedsites no longer support dormice.

Dormice are often relativelynumerous in hedgerow networks, sothe removal of hedgerows andhostile management of those thatremain has significantly reduceddormouse populations nationally.Loss of hedgerow dispersalcorridors makes it likely thatdormouse populations have become more isolated andmetapopulation connectivity hasbroken down. A metapopulation isa network of populations in alandscape, linked by occasionalmovement of animals between them.

This is likely to precipitatedormouse extinctions in isolatedwoodlands as the small populationfragments are vulnerable to poorbreeding success or inbreeding.

Hedgerow shrub diversity is linkedto dormouse abundance and

dormice are indicators of ancientbiologically diverse hedgerows.Loss of dormice from hedgerows isalso of high conservation concernbecause the dormouse is a goodindicator of biological diversity,which itself reflects the historicalinterest of the hedgerow. If thedormouse has gone, many otherspecies will have been lost too.Hedgerows with fewer shrubspecies, especially those morerecently planted in the midlands andEast Anglia, are unlikely to supportdormice. There are also regionaldifferences, even where the habitatsare suitable. For example, dormicewere found to be less abundant inhedgerows in Carmarthenshire andmost abundant in Sussex.

Hedgerows can provide a highquality habitat for dormice andpopulation densities in hedgerowsare similar to those for woodlands,sometimes reaching post-breedingdensities of 30 per ha. Populationdensity is strongly related tohedgerow height and shrubdiversity. Densities of juveniledormice are higher near to ancientwoodland, implying that hedgerows


Where hedges are poorlymaintained – especially wherestock are allowed to browse ortrample the hedge – large gapsmay develop. These severelyreduce the value of the hedge as adispersal route for dormice andfragment the available patches offood. Radio tracking reveals thatdormice will travel along hedges,but may turn back from gaps asnarrow as 3 m. Even gatewayscould be a deterrent to freemovement unless the gate isclosed and the animals can crossthe open space without descendingto the ground. The larger the gapthe greater the impediment to freemovement, denying access to thefood resources that lie beyond andreducing the extent to which thedormice can mix and interbreed.Gaps should be closed by plantingand fencing-out stock and/or bylaying existing shrubs. Suchmeasures may also be desirablefor reasons of animal husbandryand landscape considerations, andare also likely to benefit manyother species that use hedges forshelter and as dispersal corridors.

4.10 Support for habitatmanagement

4.10.1 Agri-environmentschemes

Agri-environment schemes,currently known as EnvironmentalStewardship in England and TirGofal in Wales, can providesupport for habitat managementfor dormice.

Environmental Stewardship hasthree elements:

� Entry Level Stewardship; open to all land managers.

� Organic Entry LevelStewardship; open to organicfarmers.

� Higher Level Stewardship;discretionary and concentrateson more complex types ofmanagement.

act as dispersal corridors, butdormice also breed in hedges and itis known that they establishpermanent populations in many ofthem.

Hedgerow dormice feed on bramble,dog rose and hazel, but probablymany other hedgerow shrub flowersand fruits too. Home ranges inhedgerows are longer than those inwoodlands, but cover a much smallerarea.

4.9.2 Hedgerow management

Hedgerows in arable landscapes andthose with high hawthorn contenttend to be cut most frequently. Thisis relevant because the abundance ofberries increases from one to twoyears after hedgerow cutting andthen slowly declines. Seedproduction in other species (forexample, hazel) remains low until atleast 6 years after cutting, beforebeginning to increase again.Frequent cutting of hedgerows, oftenevery year, prevents the productionof seeds and drastically reduces thenumber of flowers, nuts and berriesavailable for dormice. Hedgerowcutting intervals need to belengthened to avoid reduction indormouse numbers.

Uncut hedgerows are more likely tobe occupied by dormice, but canbecome straggly and cease to bestock-proof. A compromisemanagement programme is thereforeneeded. It is recommended thatmost hedgerows should be cut at 3-year intervals, with some left togrow for at least 7 to 10 years. It isimportant that only a minority ofhedgerows on a farm are cut in anyone year. Cutting a hedgerow on itstop has as much impact on dormousedensity as cutting on both sides.Consideration should be given tohedge laying rather than cutting,especially as this will also help toprevent old hedges from becoming‘gappy’. Laying hedges to keepthem stock-proof is a valuablealternative to installing wire fencingto close gaps, as flowering andfruiting can continue uninterrupted.

Entry Level Stewardship (ELS)and Organic Entry LevelStewardship (OELS) includeoptions for hedgerow management(EB1, EB2, OB1 and OB2) tomaintain hedges at a height of atleast 1.5 m, cut no more than onceevery 2 years; there is also anoption for enhanced hedgerowmanagement (EB3 and OB3) tomaintain hedges at a height of atleast 2 m, cut no more than onceevery 3 years, with no more than athird of the hedges cut each year.ELS and OELS also contain optionsfor the maintenance of woodlandfences and exclusion of livestockfrom woodland (EC3 and OC3);there is also an option for themanagement of woodland edges(EC4 and OC4) to encourage thewoodland edge to grow out,requiring 2 m to be left uncultivatedfrom the edge of the wood.

Higher Level Stewardship (HLS)contains an option for themaintenance of hedgerows of veryhigh environmental value (HB12).This option will allow hedgerowmanagement to be tailored to meetthe specific requirements of a targetspecies such as the dormouse.Where required, works such asplanting up gaps or establishing newhedgerow trees may be funded by aCapital Works Plan. Support is alsoavailable for woodlandmanagement, as HLS containsoptions for the maintenance orrestoration of small farm woodlands(HC7 and HC8), for example byrotational coppicing and livestockexclusion. New woodland may alsobe created (HC9 and HC10).Capital items such as planting newtrees, fencing and the provision ofdormouse nest boxes can be fundedby a Capital Works Plan. There arealso options for the maintenance,restoration or creation ofsuccessional areas and scrub (HC15,HC16 and HC17). Management canbe tailored to provide ideal scrubconditions for specific targetspecies, such as the dormouse, andmay include livestock exclusion,allowing scrub to develop naturally,or managing the scrub by coppicing.

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Further details of these options,and how to apply, can be found on Defra’s websitewww.defra.gov.uk. Environmental Stewardship ismanaged by Defra’s RuralDevelopment Service (RDS); thiswill be replaced by a new agency,Natural England, in October 2006.

4.10.2 Woodland grants schemes

The Forestry Commission operatesgrant schemes for the stewardshipand creation of woodlands inEngland and Wales. Details ofgrants are available from theForestry Commission website atwww.forestry.gov.uk.


If operations are proposed thatwould deliberately disturb, injureor kill dormice or destroy theirbreeding or resting places,protection against the possibilityof legal proceedings can beobtained in two ways:

1 Ensure that the work meets therequirement of the defence thatit was the incidental result of alawful operation and could notreasonably have been avoided.Only a court can decide what is reasonable in any set ofcircumstances and readers maywish to seek their own legaladvice as to the applicability of this defence. However,following the good practiceguidance contained in thismanual could help todemonstrate that reasonablesteps had been taken tominimise any harm.

2 Obtain a licence from Defra (or the Welsh AssemblyGovernment) to carry out thework. Licences can be issuedwhere the work is forimperative reasons ofoverriding public interest,including those of a social oreconomic nature and beneficialconsequences of primaryimportance to the environment.A licence cannot be grantedunless there is no satisfactoryalternative and the action

authorised will not bedetrimental to the maintenanceof the population of the speciesconcerned at a favourableconservation status in theirnatural range. In England,licences are issued by Defra’sRural Development Service(RDS); this will be replaced bya new agency, Natural England,in October 2006.

In order to obtain a licence, itmust be demonstrated by theapplicant that all reasonable stepshave been taken to minimise theimpact of any disturbance, andthat any damage will beadequately compensated.In practice, this means that amitigation scheme will berequired.

5.2 When is a licencerequired?

English Nature and Defra arefrequently asked by consultantswhether a Defra licence isrequired for a particular activity.Ultimately this is a decision to bemade by the consultant and client.A licence permits an action thatwould otherwise be unlawful.To minimise the risk of illegalactivities being undertaken, it isrecommended that a licence isapplied for if – on the basis ofsurvey information and specialistknowledge – it is considered that:

� The site in question isdemonstrably a breeding site or resting place for dormice.

� The proposed activity isreasonably likely to result in an offence being committed.

In addition, works can only belicensed when they meet thepurpose and conditions set out in section 5.1(2) of this manual.

No licence is required if theproposed activity is unlikely toresult in an offence. The advicegiven in this document shouldassist a consultant in arriving at a decision on this matter, though it must be recognised thatdetermining whether a particularsite is used as a breeding orresting place can be problematic.Note that if the proposed activitycan be timed, organised andcarried out to avoid committingoffences, then no licence isrequired.

Examples of works that are likely to need a licence include:

� Clearance of woodlandinhabited by dormice fordevelopment or road schemes.

� Removal of hedgerowsinhabited by dormice forpipeline schemes or building works.

5 Development and mitigation

The dormouse is a European protected species. It is protected from deliberate killing, injury or

disturbance and its breeding sites and resting places are absolutely protected with no requirement to

show that their destruction was deliberate or reckless. Exactly what constitutes a breeding site or

resting place for a dormouse has not been defined in case-law, but a narrow interpretation might include

nests (summer or winter) currently in use or, perhaps, built or used during the current season. Because

the dormouse is so embedded in its habitat and nests are difficult to find, a pragmatic approach is to

treat any dormouse habitat as though it is protected and develop mitigation based on this assumption.

This approach is also compliant with the duty to have regard to the conservation of biodiversity imposed

on Government Departments by S74 of the Countryside and Rights of Way (CRoW) Act 2000.

5.1 Legal background and licensing

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5.3 Possible impacts fromdevelopment

Dormice may be threatened bydestruction of their habitat, forexample when woodland is clearedfor development or conversion toother uses. Hedgerows may beremoved as part of suchdevelopments or in the course offarm management. Radiotrackingand surveys have demonstratedclearly the importance for dormiceof linear features in the landscape,especially hedges. The loss ofhedges, leaving remnant groups ofdormice isolated in the landscape,can be very damaging. A typicalexample may be where a smallcopse is protected fromdevelopment but is left isolatedfrom larger areas of habitat anduseful food resources. New roadsand the widening of existing onesare also a threat, not just becauseof the destruction of dormousehabitat (for example, by removalof roadside hedges), but alsobecause a new road is likely to bewider than the old. Thisconstitutes a greater barrier todispersal and will probably reducemovements between localpopulations. In the long term, thisfragmentation of habitat andreduction of dispersal potentialmay be a greater danger than themore obvious threat posed by thedestruction of a woodland site.

The long-term impact of increased human activity shouldalso be considered when decidingon appropriate mitigation,particularly where high densityhousing is being built adjacent tohabitat that previously was rarelyvisited by people.

Direct modifications to sites,including the felling of trees orscrub clearance, can have asignificant impact on dormice.Even where trees and shrubsremain largely unaffected, or wherework is done in winter, there maystill be significant implications forhibernating dormice and the placeswhere they overwinter.

Activities associated withdevelopment works are likely to lead to an increase in humanpresence at the site, extra noiseand changes in the site layout andlocal environment. All these may have a detrimentaleffect on dormice, their needs forparticular environmentalconditions (such as specifictemperature and humidityregimes), and a stable landscapethat allows them to followestablished routes to feed (seebelow). Sometimes it may bepossible to lessen the impact, ormeasures may be taken to help thedormice through a difficult period.

5.4 Predicting likely impacts

The task of determining the impactof a proposed development is madeeasier by good survey informationand detailed plans, showing pre-development and post-developmentsite layout in relation to the placeswhere evidence of dormice hasbeen found. Sometimes called ‘impact assessment’, this is acritical phase of mitigationplanning. This assessment can alsohelp in considering alternative sitesor alternative site layouts. Forcertain types of project, listed inschedules of the Town and CountryPlanning (Environmental ImpactAssessment) (England and Wales)Regulations 1999, impactassessments are mandatory(Schedule 1) or discretionary(Schedule 2). Even when astatutory impact assessment is notrequired, Local PlanningAuthorities do have powers (forexample, under the Town andCountry Planning (Applications)Regulations 1988) to directdevelopers to provide anyinformation the Authority mayreasonably require to enable it todetermine the application. TheHigh Court has ruled (R. v.Cornwall County Council ex parteJill Hardy, 22 September 2000) thatfor developments requiring anEnvironmental Impact Assessment(EIA), where there are grounds forbelieving that protected species

may occur, environmentalinformation (primarily surveyresults) has to be provided to theLocal Planning Authority beforedetermination. Initial surveys todetermine the presence of protectedspecies should not be a conditionof the planning permission. Itseems logical that these principlesshould also apply to non-EIAdevelopments, since the guidancein the legal circular accompanyingPlanning Policy Statement 9:Biodiversity and GeologicalConservation (PPS9) regardingprotected species being a ‘materialconsideration’ is difficult, if notimpossible, to implement where nosurvey information exists. Ideally,an impact assessment shouldinform the drawing up of detaileddevelopment plans, so that impactscan be avoided where possible. Itis therefore important that a surveyis undertaken as early as possiblein the planning process.

It is desirable to consider directand indirect impacts, both at thesite level and in a widerperspective. The latter relates tothe assessment of the overallimportance of the site, and the broad context of the site should also form part of the impact assessment.

Timing should also be considered. If the site is part of a larger phased development,the potential consequences for the affected population(s) duringlater stages of the work also needto receive attention. For example,planting new habitat, only to haveit destroyed during a later phaseof development, does notconstitute mitigation.

5.5 Roles and responsibilities

It is the responsibility of theorganisation or individual wishingto carry out the development tomake sure that they comply withthe law. In practice, developersmay wish to employ a specialistenvironmental consultant to carryout any survey, make


recommendations and, if necessary,apply for a licence. The statutorynature conservation organisations(English Nature or the CountrysideCouncil for Wales) can providegeneral advice on protected species,advise Local Planning Authoritieson specific planning issues andassist the licensing authority withthe determination of licenceapplications. Further informationabout the roles of the organisationsinvolved is given in Chapter 10.

5.6 Planning mitigation andcompensation

5.6.1 Why mitigate?

Minimising the impact ofdevelopment on dormice isfundamental to meeting therequirements of the licensing regimewith its tests of no reasonablealternative and imperative reasonsof overriding public interest.

The aim of the consultant anddeveloper should be to achieveone of the following outcomes, indecreasing order of preference.Each of these scenarios should bedesigned to satisfy Regulation44(3)(b) (see Section 6.1):

� Most preferable. Avoidanceof impact; no negative impacton dormouse populations.

� Minimisation of impact with on-site mitigation;compensation by theimprovement of existingnesting and feeding sites or theprovision of new opportunities(such as nest boxes) within thesite. Maintenance orreinstatement of hedges andtree lines linking wooded areas.

� Minimisation of impact withoff-site compensation; whereon-site mitigation is notpossible, new habitats shouldbe created nearby.

� Least preferable. In somesituations, translocation ofdormice may be needed.

The potential impacts of thedevelopment should be consideredat the outset, so that, wherepossible, plans can be modified inorder to achieve the preferredoutcome listed above. This couldentail the development ofalternative sites, or the repositioningof structures to avoid impacts. Notethat Defra licences to destroybreeding or resting places can onlybe obtained where there is nosatisfactory alternative to thatcourse of action. If impacts can beavoided completely the HabitatsRegulations are not contravened andno licence is required.

5.6.2 Key principles of mitigation

Strictly speaking, there are twoelements to the broader mitigationprocess:

� Mitigation – in the strict sense,refers to practices that reduce oravoid damage (for example, bychanging the layout of a scheme,or altering the timing of work).

� Compensation – refers to workthat offsets damage caused by adevelopment (for example, bythe creation of new habitat).

Both these elements need to beconsidered, the overall aim beingto ensure that there will be nodetriment to the conservationstatus of dormice. In practice, thismeans maintaining and,preferably, enhancing populationsaffected by development.

The following points should beconsidered when planningmitigation:

� Mitigation should beproportionate. The level ofmitigation required depends onthe size and type of impact, andthe importance of the populationaffected. This is a complex site-specific issue. For example, aminor car park extension in anarea of Kent where dormice arewidespread would require lessinvestment in mitigation than a

major road driven through oneof the few dormice sites innorthern England.

� Plans should be based onadequate knowledge. Thoroughsurveys, site assessments andimpact assessments are essential.The development plan shouldconsider each predicted impactand suggest how it can be avoided,lessened and/or compensated for.The seasonal nature of dormouseactivity may mean that surveywork lasts for more than one year.

� Mitigation should aim toaddress the characteristicspicked up by the siteassessment. There should beminimal net loss of suitablehabitat. Where significantimpacts are predicted,compensation should offer morethan has been lost. Thereasoning behind this concept isthat the acceptability of newlycreated habitat to dormice is notpredictable. In addition, not allthe new habitat may beimmediately available due to thetime it takes for planted shrubsand trees to bear fruits andflowers. Plans should aim tocreate similar habitat types (forexample replace hazel coppicewith hazel, not sweet chestnut)though it must be recognised thatancient woodland is irreplaceable.Compensation measures shouldensure that the affected dormousepopulation can function asbefore. This may requireattention to the environmentaround the development site,such as planting hedges to linkadjacent habitats.

� Preparing a site orappropriate replacement mayrequire considerable timeand effort. For high impactschemes, additional land mayneed to be purchased, increasingthe costs of compensation.Depending on circumstances, along period of time may beneeded to develop new plantingsinto suitable habitat for dormice.

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� The long-term security of thepopulation should be assured.Mitigation should aim to ensurethat the population will be freefrom further disturbance, andwill be subject to adequatemanagement, maintenance andmonitoring. Any proposalsshould be officially confirmed –ideally by a legal agreement orplanning obligation – and not leftas open-ended options.

� Mitigation plans will be opento public scrutiny.English Nature and Defra willmake plans available to thirdparties on request whereverpossible, as required byfreedom of informationlegislation. If submitted as partof a planning application, planswill also be held on file byLocal Planning Authorities andbe available for public viewing.

� Mitigation plans shouldaddress the impacts of allstages in phased developments.Individual phases will normallybe mitigated for individually, butthere should be an overall planthat takes the impacts for theentire scheme into consideration.

Precautionary mitigation (that is,going ahead with mitigation before aproper survey has been undertaken)is not normally acceptable. Anexception might be where there isgood evidence to indicate that thesite is of very low importance andthere will be negligible impacts.

5.7 Mitigation andcompensation methods

5.7.1 Introduction

This section gives advice on themethods commonly used formitigation and compensation,paying particular attention to effortand timing. These are not the onlymethods that could be used, butthey are generally effective andshould be considered as goodpractice applicable to the majorityof development schemes. As sites

vary in their characteristics, andwill have different impacts, theinformation presented here isgeneric rather than prescriptive;licence applicants may make a casefor different techniques and levelsof effort on a site-by-site basis.

It is the responsibility of theapplicant (normally the consultantand their client) to make sure thatany proposed mitigation meetsother legal requirements.

5.7.2 Avoidance of disturbance,killing and injury

The Habitats Regulations andWildlife & Countryside Act areconstructed to give protection toindividuals as well as breeding sitesand resting places. This means thatprecautions must be taken to avoidthe deliberate killing or injury ofdormice, an action that is mostunlikely to be permitted under theterms of a licence. Disturbance ofdormice or destruction of their nestsmay be permitted under licence, butconditions are likely to apply.

Where habitat suitable for dormicewould be unavoidably lost as a resultof development, the extent of thisloss will determine the appropriatecourse of action. Where habitat losscan be limited to a strip of woodlandor scrub less than 50 m wide, or itsequivalent, (less than the radius of atypical dormouse home range) andthis strip remains linked to a largercontinuous area of dormouse habitat,then displacement of the residentanimals is the most appropriate option.This is also the most appropriateoption where less than 100 m ofhedgerow would be removed. Wheregreater areas (or lengths of hedgerow)need to be removed in any onelocation and in any one season, thentranslocation of the animals shouldbe considered (see below).

5.7.3 Clearing dormice from asite prior to development

If an area of dormouse habitat needsto be cleared for development (forexample, in a road widening

operation), its type, size andposition relative to other habitat are key issues in determining themost appropriate mitigation strategy. If the site is large or isolated, orperhaps only linked to one smallhedge, then the dormice may haveto be translocated, otherwisepersuasion (see below) is themethod of choice, provided that it does not result in more thandoubling the spring populationdensity in the remaining habitat.

Persuasion

If the land to be cleared forms part ofa larger continuous area of dormousehabitat (a strip along the edge of awood for example), then persuadingthe animals to leave by progressivelyclearing narrow strips of habitat isrecommended. Each strip should benarrower than the radius of a typicalhome range for that habitat (anaverage of 50 m) encouraging thedormice to leave the area as thehabitat becomes unsuitable. Thedormice will then relocate of theirown accord into the adjacentundisturbed habitat, especially ifattractive features such as nestboxes are present there. However,deploying nest boxes betweenOctober and April will have nouseful effect until the followingsummer as dormice do not normallyuse them during the winter.

Clearance in winter

This should remove sufficientvegetation to persuade dormiceemerging from hibernation in Aprilor May to move to more appropriatehabitat nearby. Once emergence iscomplete, by the end of May, fullclearance of the area can continue.Winter clearance should thus beplanned as a two-stage process.

Trees and shrubs within the area inquestion should be cut down betweenNovember and March inclusive, toavoid both the bird nesting seasonand the majority of the period whendormice might be found in nestsabove ground. Clearance should bedone by hand and in a sensitive


manner, to minimise the likelihoodof disturbing or killing hibernatingdormice. Similarly, the process ofremoving the cut material should, asfar as possible, be designed to protectdormice hibernating on the ground.This can involve such techniques as:

� sacrificing a single ‘haul-route’, which has first beencleared by hand if necessary;

� using a long-reach mechanicalgrab and/or limiting thenumber of ‘drag-lines’ alongwhich stems are removed;and/or

� directional felling to minimisethe ground impact.

In some cases it is possible toleave felled stems until later in theyear (brash should however beremoved or chipped to avoidsubsequent constraints associatedwith nesting birds). There willalways be some parts of the sitewhere hibernating dormice will bemore at risk. In these situations,careful raking over of leaf litterand moss on the ground and thehand-clearance of log piles mayhelp to find a few hibernatingdormice before the machinesmove in. However, searchinglarge areas is impractical.

In parallel with clearanceoperation, work should beundertaken within the retainedwoodland, hedgerow or scrub toincrease its carrying capacity fordormice. This can include carefulfelling or coppicing work toincrease the fruiting of selectedunderstorey shrubs. Similaroperations can also help form anew woodland ‘edge’ in situationswhere previously sheltered treesbecome exposed to wind-throw.Where there are few opportunitiesto improve adjacent areas fordormice, consideration should begiven to advance planting of newareas nearby, or reducing the levelof management in any adjacenthedgerows. The provision of nest-boxes can also be helpful.

Dormice emerging fromhibernation in cleared areas willtend to move into the nearestretained vegetation. The coppicedstools in the cleared areas shouldthen be dug up (usually in parallel with other earthworks), but thisshould be done no earlier thanMay of the following season.At this point consideration couldbe given to translocating some ofthis material to create new habitat,as explained below.

Even if quite small areas of habitat need to be cleared, thepositions of these relative to other suitable habitat is a keyissue. If parts of the site are soisolated that dormice hibernatingthere would not be able to reachareas of retained habitat, measuresneed to be taken to catch andremove these animals; either well in advance of clearance orfrom those fragments of habitatthat remain following thecoppicing works.

If larger areas of woodland are to be cleared for development, it may be necessary to repeat theabove over more than one winter.Care should be taken to ensurethat dormice displaced over onewinter are not displaced again the next year.

Similar principles apply to hedgeclearance, where clearance byhand or with hand-held machineryshould avoid disturbance to thebase of the hedge, where dormicemay hibernate. Using heavymachinery to grub out hedges islikely to destroy dormice in theirhibernacula.

Clearance in summer

Summer clearance is suitable forsmall areas of dormouse habitat(for example, less than 50 squaremetres of high quality woodland,larger areas of low quality habitatand short lengths of hedge). Thismay be done by taking out smallamounts of vegetation onsuccessive days at a time of year

when the animals are active andable to respond immediately.Such clearance should be done byhand and should be combined withsearches for nests. Clearance inMay will avoid separating femalesfrom dependent young, but theremay be a conflict here withnesting birds, at least up untilabout July. After early June,female dormice are likely to haveyoung in their nests until aboutlate September (depending onlatitude and weather).

Whichever season is chosen forclearance, care should be taken to ensure that the number ofanimals displaced does not resultin unnaturally high densities inthe remaining woodland. As arule of thumb, clearance of morethan 10 per cent of any woodland(or woodland complex if well-connected) should beavoided. For example, a 10 hawood may be capable ofsupporting a post-breedingpopulation of 10 dormice per ha.Clearance of a single hectare (10 per cent) of this woodlandover the winter might displacefive dormice in the spring(allowing for 50 per cent mortalityover the winter), resulting in atotal population in the remaining9 ha of 50 dormice or 5.5 per ha,well within the carrying capacityof the woodland.

Translocation

Where persuading dormice torelocate from a site isinappropriate, either because ofthe scale of the proposed operationor the lack of suitable adjacenthabitat, the only remainingsolution is to translocate theanimals. This is the least favouredoption because of the difficulty ofcatching all the animals andestablishing them at an appropriatesite elsewhere. Where a large areaof dormouse habitat has to beremoved in a single season,translocation is the only option,but a suitable recipient site mustbe identified in advance.

Guidance on translocation (andreintroduction) is given elsewhere inthis manual, but it should be notedthat translocation requires muchpreparatory work and findingsuitable release sites can be difficult.Releasing translocated dormice intosites with existing populations isunlikely to be acceptable to thelicensing authorities.

Dormice may be trapped forremoval, but this requires largenumbers of suitable traps as theanimals live at low densities. Thetraps need to set off the ground andinspected twice a day, a labourintensive and costly process. Abetter method is to put up nest boxesat a density of at least 30 per ha.These should be in place well inadvance of work at the site,preferably a year or more beforehandif possible. As a minimum, the nestboxes should be put up by early Mayand left in place until late October.The dormice should then use theboxes and be easily caught. Nestboxes should be left in place andinspected frequently until no moredormice appear in them. This willonly be successful when the dormiceare active (May to October) and itmay take many weeks before theanimals begin to use the nest boxes.Capture efficiency varies seasonally,

and there is generally a dip in nest-box usage in June and July (seeTable 5). Nest tubes may also beused for this purpose and there maybe benefits in using a combination oftubes and boxes to maximise thenumber of dormice caught.

It is difficult to know when all thedormice are likely to have beencaught, especially as others maymove into the site during a removaloperation. Table 2 gives anindication of the population densityassociated with different habitats,though these are spring pre-breeding densities. In late summer,good woodland habitat may havemore than 10 individuals per ha andlarge hedgerows may have up toone adult pair per 300 m. Clearinga 50 m length of hedge where itadjoins other dormouse habitat mayreduce recolonisation whileremoval operations are in progress.

5.7.4 Minimising and repairinghabitat damage

So far as possible, removal of hedgesshould be avoided, as should theremoval of large fruiting hazels andoaks. Removal of other species froma mixed woodland (for example, ash,holly, conifers) is unlikely to havesignificant effect except where their

Persuasion – good practice summary

� For areas of up to one dormouse home range (approximately 1 to 1.5ha of woodland or 300 m of hedge) clearance of bushy vegetation andtree felling in winter (November to March inclusive) is recommended asthe least-damaging option. At this time, dormice will be hibernating innests just below ground level and are vulnerable to crushing so everyreasonable effort should be made to minimise disturbance to theground. Clearance should therefore be planned as a two-stageoperation, with removal of surface vegetation in winter followed bystump extraction and earth removal in the following summer.

� For smaller areas – including short lengths of hedgerow – clearance insummer is an acceptable alternative. Small amounts should be taken outeach day to allow animals time to escape, and a search should be madefor nests. The best times for this work are May and late September,when there is less likelihood of young being present in nests.

� Whichever method is used, care should be taken that the clearance doesnot result in an unnaturally high population density in the remaining area.

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removal breaches access points anddisrupts the continuity of dispersalroutes. Planting hedges, particularlywith a variety of shrubs, links upisolated copses and individual trees,thus helping the exchange betweensmall dormouse populations andproviding access to a wider range offood sources. This may be avaluable conservation option for newroad construction, which often leavessmall hedge and woodland fragmentsisolated from each other. Plantingshould begin as early as possible,preferably before other operationsbegin and not after clearance hasbeen completed. This is to allow thenew shrubs time to flower and fruitbefore the old habitat is removed.Planting bramble and other usefulfood plants is valuable if they fruitwithin the first year. Dormice cannotwait five years for hazel to mature!

Where heavy machinery is alreadyon site, transplantation ofvegetation (especially hazel stools)that would otherwise be uprootedand chipped or burnt can be ahelpful and cost-effective measure.

Transplanting during the winter mayachieve 100 per cent survival, evenwithout watering, but after about Maywatering will be necessary or survivalrates will be reduced. Shrubs movedin this way will fruit much earlier andmore heavily than new saplings.In addition, transplanted shrubs willenhance arboreal connectivity, againat a much earlier stage, andparticularly if combined with the‘dead-hedging’ of cut material. If this is seen as a key aspect of amitigation scheme, it should be donesensitively and with appropriateaftercare, in order to maximise thelikelihood of survival and vigour ofthe transplanted material. Transplantsmay also reduce the visual impact ofnew developments. See Anderson & Groutage (2003) for guidance onhabitat translocation.

Where strips of woodland edge areremoved, or mature woodland isbisected, a ‘wall’ of high treesremains at the edge of the clearedarea. In these cases it is better to

clear a few extra metres, then planta fringe of species-rich shrubs.These will grow quickly, healingthe visual scar and providingabundant food and shelter fordormice and other species.

Where possible shrubs and treesshould be planted to fill in small gapsor to link habitats, in particular tolink new plantings with existing areasof dormouse habitat. The HighwaysAct 1980, Section 253 allows forwork to be carried out on third-partyland for mitigation purposes, at leastin respect of road developments.Again, such work should be started assoon as possible to allow time formaturation, and some landownersmay be sympathetic to an early startin advance of the main operations.

5.7.5 Dormouse bridges andtunnels

Roads and other developments cancause significant incidental damageto populations of dormice byfragmenting habitats and creatingbarriers to natural movement. Thisis a particular problem for dormicebecause of their reluctance to crossopen ground, but it is also animpediment to the dispersal of manyother animals, for example reptiles,spiders and molluscs.

Habitat continuity and naturaldispersal movements can be retainedby building ‘green bridges’ to permitanimals to cross roads and othernewly-constructed barriers. Fordormice, the cheapest form ofoverhead link is a pole or ropestretched between two substantialtrees. Whilst this might be a feasibleoption within a wood (for example totemporarily bridge a narrow ridewhile arboreal links regrow) it isprobably not applicable to largerscale situations. Although ropes havebeen suggested as a mitigationmeasure (Highways Agency 2001)there appears to be no publishedscientific evidence that dormiceactually use them, but it remains apossibility. Ropes will be used (overshort distances) by squirrels, andwooden structures (such as horizontalladders) have been used elsewhere toassist monkeys to cross roads.If ropes are to be tried for dormice,they should be taut and stabilised bylateral supporting ropes leading toadjacent habitats at 5 m intervals.It is very unlikely that dormice willoften venture more than a few metreson such an exposed structure, asradiotracking shows that they arenormally only active within cover.

A cylindrical wire cage around therope, made of welded mesh, mighthelp to stabilise a structure andprovide greater protection for dormice,while allowing them to get a bettergrip. A tubular cage-type structure,formed into a suspension bridge,

The dormouse conservation handbook - second edition 51

Figure 17 Dormouse bridge. This structure was designed to help Japanesedormice Glirulus japonicus across a new road and carry road signage.

might also offer a way forward andshould be tested for use by dormice.It is likely that short bridges, whatevertheir construction, will be more likelyto be used than longer ones and thatattempting to bridge gaps of morethan 100 m will be largely ineffective.

In Japan, a dormouse bridge has beenbuilt, based on a welded steel frameof the sort normally used forsupporting road navigation boards.It is about 50 m long and there isclearance for large lorries to passbelow. The bridge itself is about 1 mwide x 1.5 m high, and is encased inwelded mesh to protect the animals.The floor is made of wooden boardsalong which lie a selection ofbranches cut from nearby trees. Ateach end, ropes and planted climbingvegetation link the bridge with theadjacent forests. The bridge wasused within a few weeks by Japanesewood mice and within a year byJapanese dormice. The bridge wascustom-made and expensive but asimilar bridge might be constructedmore cheaply, based on a standardoverhead gantry used for highwaysignboards. Alternatively, suitablefacilities might be built into existinggantries or as ‘add-ons’ to plannedstructures. Some structures of thistype are currently being trialled in Britain, though their success has yet to be demonstrated.

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In some parts of Europe, concrete ‘green bridges’ have been constructed with shrubs andother natural vegetation planted on top of them. In Germany,dormice have been shown to usesuch structures. However, muchwould depend on the nature of theshrub layer and how effectively it was integrated with the naturalhabitats at either end of the bridge. Some details andillustrations of habitat bridges aregiven in Iuell and others (2003),and one has been built over theLamberhurst bypass (A21) in Kent and opened in 2005.Such bridges are expensive, butmay benefit a variety of species,particularly those with lowdispersal potential such as reptiles and invertebrates.

As an alternative to bridges, it maybe possible to maintain habitatconnectivity by planting shrubs intunnels and culverts. This is onlylikely to be successful where thetunnel or culvert admits enoughlight enough to sustain plantgrowth. An example is shown onthe cover, though the success ofthis form of mitigation is unknown.

5.8 Nest boxes

Provision of suitable nest boxeswill help dormice adjust to newlycreated or modified habitats,particularly where new plantingsmean a scarcity of natural treehollows. Nest boxes appear toincrease the ‘carrying capacity’ ofthe habitat, sometimes doublingthe population density (Morris andothers 1990). In addition, nestboxes benefit other species,including many invertebrates.Other mammals may also usethem including bank voles, shrewsand bats. Clearly provision of nestboxes is helpful in a broader sensethan just dormouse conservation.However, this applies to boxes,not nest tubes. Plastic nest tubesare not adequate compensation forthe loss of permanent nest sites.

5.9 Hibernating dormice

Sometimes hibernating dormiceare disturbed accidentally duringhedging, woodland managementoperations or site clearance. Ifpossible, the animal should bequickly wrapped up in its nestand replaced, perhaps with a light

Reducing site damage: good practice guidance

In some cases, site destruction is unavoidable, but the damage may be reduced by:

� Limiting the use of heavy machinery for site clearance in winter, when dormice will be helpless in theirhibernacula on the ground. They will be easily crushed, and in their inactive hibernating state, unable to help themselves.

� Carefully raking over leaf litter and moss on the ground in winter and clearing log piles by hand may find afew hibernating dormice.

� When clearing small sites, carrying out site activities in spring or late summer when the risk to dormice isreduced. Moreover, if clearance proceeds progressively from one edge of the site it may be possible to persuadethe animals to move away into refuge areas over several days.

� Putting up nest boxes in refuge areas may entice at least some animals away from danger, but only in summer.

� Leaving mature oaks and other valuable trees wherever possible, and then using shrubs to link trees to eachother and to areas of remnant woodland.

� Planting species-rich hedges to link isolated woodland remnants or reconnect remnants of damagedhedgerows. In the long term, this will allow the interchange of small mammals (including dormice), soreducing the dangerous effects of isolation.

covering of leaves, moss ortwigs. If the site is to bedestroyed or extensivelytrampled, transfer the nest and its occupant – with plenty ofdamp padding – to a more secure place within 100 m, on the ground (for example, tuckedunder the curve of a large log) or between the roots of a tree orbush. A large roof tile or suitablysupported paving stone may beplaced to cover the nest,protecting it from predators andhelping to maintain moist andcool conditions. It is harmful forhibernators to be exposed toextreme frosts, but it is alsodamaging, and more common, tobecome too warm. This wouldbe the case if the sun shone on ahibernation nest for an hour orso. The animal should only beremoved as a last resort. If it istaken away, or caused to arousefully, it should be kept in captivity and not returned to thesite until the summer. On returnit should be released within 100mof its origin. Dormice should notbe released at a site unfamiliar tothem without full support (seeChapter 7).


The dormouse was given partialprotection under the Wildlife and Countryside Act 1981. Schedule 5 of this Act wasamended in 1988 making it a fully protected species.Protection is also afforded bySchedule 2 of the Conservation(Natural Habitats &c.) Regulations 1994, making thedormouse a European protectedspecies. These two pieces oflegislation operate in parallel,although there are some smalldifferences in scope and wording.

The Wildlife and Countryside Act1981 (WCA) transposes into UKlaw the Convention on theConservation of European Wildlife and Natural Habitats(commonly referred to as the‘Bern Convention’). The 1981 Act has been amended severaltimes, most recently by theCountryside and Rights of Way[CRoW] Act 2000, which added‘or recklessly’ to S9(4)(a) and (b).Dormice are listed on Schedule 5of the 1981 Act, and are thereforesubject to the provisions ofSection 9, which makes it anoffence to:

� Intentionally kill, injure or take a dormouse [Section 9(1)].

� Possess or control any live or dead specimen or anything derived from adormouse [S 9(2)] (unless it can be shown to have been legally acquired).

� Intentionally or recklesslydamage, destroy or obstructaccess to any structure or place used for shelter orprotection by a dormouse [S 9(4)(a)].

� Intentionally or recklesslydisturb a dormouse while it is occupying a structure orplace which it uses for thatpurpose [S 9(4)(b)].

The Conservation (Natural Habitats&c.) Regulations (known as theHabitats Regulations) transposeinto UK law Council Directive92/43/EEC of 21st May 1992 onthe Conservation of NaturalHabitats and of Wild Fauna andFlora (often referred to as the‘Habitats [and Species] Directive.’).Dormice are listed on Annex IV(‘European protected species’) ofthe Directive meaning that memberstates are required to put in place asystem of strict protection asoutlined in Article 12; this is donethrough inclusion on Schedule 2 ofthe Regulations. Regulation 39makes it an offence to:

� Deliberately capture or kill adormouse [Regulation 39(1)(a)].

� Deliberately disturb adormouse [R. 39(1)(b)].

� Damage or destroy a breedingsite or resting place of adormouse [R. 39(1)(d)].

� Keep, transport, sell orexchange, or offer for sale orexchange a live or deaddormouse or any part of adormouse [R. 39(2)].

6.2 Interpretation andenforcement

As the legislation referred to aboveapplies to a wide range of species,not just dormice, its provisions aregeneric in nature. For example,there are no detailed definitions of exactly what constitutes a

‘resting place’ for a dormouse, norwhat has to be proved to establishthat an act could not reasonablyhave been avoided. Were a breachof the law to be alleged, a courtwould have to decide whether anoffence did in fact occur. Notethat, under the 1994 HabitatsRegulations, damaging ordestroying a breeding site orresting place is an offenceregardless of whether the act was deliberate or not. There arecurrently no legal precedents (that is, cases in the Crown Court or higher) that are helpful in interpreting what constitutes aplace used for breeding and resting.

The Police are the mainenforcement body for wildlifeoffences, and in some cases LocalAuthorities may also take action.Section 24(4) of the 1981 Actgives English Nature (or the CCW)the function of providing advice orassistance to the Police in respectof alleged offences. Themaximum fine on conviction foroffences under Section 9 andRegulation 39 currently stands at£5,000. The Countryside andRights of Way (CRoW) Act 2000amended the 1981 Act to allow fora custodial sentence of up to sixmonths instead of, or in additionto, a fine. Penalties may beimposed in relation to each offencecommitted, so operations involvingmany animals or repeated offencescan potentially accrue large fines.In addition, items which mayconstitute evidence of thecommission of an offence may beseized and detained. The CRoWAct 2000 also amends the Policeand Criminal Evidence Act 1984 torender Section 9 offences‘arrestable’, giving the policesignificant additional powers.

6 Legislation, legal status & licensing

The hazel dormouse is a fully protected species under both United Kingdom and European law.

It is also included in the UK Biodiversity Action Plan as a priority species.

6.1 Relevant direct legislation

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6.3 Exceptions and licences

There are several exceptions(defences) to the provisions listed insection 6.1 above. For example, adisabled dormouse may be lawfullycaptured solely for the purpose ofrestoring it back to health forsubsequent release, and ‘mercykilling’ of severely injured dormiceis also permissible without a licence.Both the 1981 Act and the HabitatsRegulations provide a defence to theoffences listed in section 2.1 abovein cases where “the act was theincidental result of a lawfuloperation and could notreasonably have been avoided.”[S. 10(3)(c) of the Wildlife andCountryside Act and Regulation 40(3)(c) of the Habitats Regulations].

English Nature can issue licences toallow otherwise prohibited actions(such as catching and handlingdormice) for scientific oreducational purposes. This coversmarking them, conservation work,photography or protectingzoological collections. Applicationsshould be made to the LicensingSection, English Nature,Northminster House, Peterborough,PE1 1UA. Similar licences forwork with dormice in Wales areavailable from the CountrysideCouncil for Wales, Maes y Ffynnon,Penrhosgarnedd, Bangor, Gwynedd,LL57 2DW. There are no dormicein Scotland. Licence applicationsshould be supported with evidenceof competence in the activities forwhich a licence is required, such asprevious attendance at a dormousetraining course or working with acurrent licensee. A licence may berefused unless suitable knowledgeand experience (especially ofhandling) can be demonstrated.

Licences in connection with publichealth or safety, prevention of thespread of disease or the preventionof serious damage to livestock,crops or other property are availablefrom the Rural DevelopmentService (RDS) of the Departmentfor Environment, Food and RuralAffairs (Defra) or, in Wales, the

Welsh Assembly Government.Since dormice do not carry seriousdiseases or do significant damage, itis unlikely that these provisions willapply. In addition, these authoritiesissue licences for the purposes of“preserving public health orpublic safety or other imperativereasons of overriding publicinterest including those of a socialor economic nature and beneficialconsequences of primaryimportance for the environment.”

In every case, a licence cannot begranted unless:

“There is no satisfactoryalternative”; and

“The action authorised will notbe detrimental to themaintenance of the populationof the species concerned at afavourable conservation statusin their natural range.”

‘Favourable conservation status’ isdefined in the Habitats and SpeciesDirective (Article 1(i)).Conservation status is defined as“the sum of the influences actingon the species concerned thatmay affect the long termdistribution and abundance of itspopulation within the territory.”It is assessed as favourable when:

“population dynamics data on thespecies concerned indicate that itis maintaining itself on a longterm basis as a viable componentof its natural habitats”:

“the natural range of the speciesis neither being reduced nor islikely to be reduced for theforeseeable future”; and

“there is, or will probablycontinue to be, a sufficiently largehabitat to maintain itspopulations on a long term basis.”

Further information about theoperation of this licensing regimeas it relates to development is givenin Chapter 5. Note that a newAgency, Natural England, will take

over the licensing roles of EnglishNature and the Rural DevelopmentService in October 2006.

This is only a general guide to themain provisions of the law. TheWildlife and Countryside Act 1981and the Conservation (NaturalHabitats &c.) Regulations 1994should be consulted for furtherdetails.

6.4 Incidental protection

The dormouse is also incidentallyprotected by the HedgerowRegulations 1997, which are intendedto prevent removal of importanthedgerows. The criteria for definingan important hedgerow include arecord of the presence of any speciesprotected by Schedule 5 of theWildlife and Countryside Act withinthe 5 years before the passing of theAct (that is, the period from March1992 to March 1997). Approval ofthe Local Authority is required beforesuch a hedge is removed and there isan appeals process involving theSecretary of State. Environmentalassessments are required (underEuropean Directive 82/357/EEC, asamended), where proposals for newroad developments and forimprovement of existing roads areconsidered to have significantenvironmental effects. TheDirective is enacted in the UK by theamended Highways (assessment ofenvironmental effects) Regulations(1988), for motorways and trunkroads, and the Town & CountryPlanning (assessment ofenvironmental effects) Regulations(1988), as amended, for localauthority and private roads andassociated works. Effectively, theseregulations require that actual orpotential presence of protected speciesbe taken into account when majordevelopments are planned. Surveysare required to confirm presence orlikely absence of protected species.In the former case, mitigationmeasures must be implemented tocompensate for the damage done toprotected species, so as to avoidtheir local extinction as a consequenceof the planned development.


The UK Government is asignatory to the Convention onBiological Diversity (‘The RioConvention’) and consequentlycommitted to conserving andenhancing biodiversity. This isgiven force by the Countrysideand Rights of Way Act 2000(Section 74), which imposes aduty on Ministers and Government departments to have regard to the purpose ofconserving biological diversitywhen carrying out their functionsand also to take appropriate stepsto further the conservation oflisted priority species.

6.5 Planning policy

Planning Policy Statement 9 (PPS 9):Biodiversity and GeologicalConservation embodies theGovernment's commitment toconserving biodiversity through theplanning system and states that thepresence of a protected species is a‘material consideration’ inassessing a development proposal.The guidance sets out policy as itrelates to nature conservation inEngland and, although onlyadvisory, it can be seen asproviding guidance on goodpractice in the planning system.

PPS9, which is accompanied by alegal circular and good practiceguidelines, also offers guidance onthe roles and responsibilities ofLocal Planning Authorities andstatutory nature conservationorganizations, with regard todevelopment control affectingSSSIs and other designated sites.It is particularly relevant to LocalAuthority road schemes andassociated developments such asservice areas. The equivalentdocument in Wales is the PlanningGuidance (Wales) TechnicalAdvice Note (TAN) 5 – NatureConservation and Planning.


7 Captive breeding and reintroductionto the wild

Rescued animals or those foundby accident should be released ifpossible where they were found,or kept until further advice isobtained (from English Nature orthe Common Dormouse CaptiveBreeders Group, c/o PaigntonZoo Environmental Park, DevonTQ4 7EU). Dormice taken intocaptivity temporarily for welfarereasons should be fed fresh fooddaily (apple, carrot, grapes) withnuts, biscuit and seeds providedin quantity. Fresh water mustalways be available. Adult malesmust be caged separately, butmay be accompanied by one ormore females. Each animalshould have its own nest box,even if they choose to share thesame one. Fresh hazel or othertree branches should be providedso the dormice do not lose theiragility, reducing their success inthe wild. Dormice should not beencouraged to become tame orthey may be insufficiently waryof predators after release. Cagesmust allow plenty of verticalspace for climbing and shouldideally provide more than 0.75cubic metres per animal. A deeptray in the floor of the cageshould be filled with soil or peat,covered with moss. This willprovide a place to hibernate. Thesoil should be kept damp byweekly spraying with water

throughout the winter otherwisethe hibernating dormice maybecome dehydrated.Hibernation is unlikely to besuccessful in a conservatorywhere the temperature may often be too warm in winter,causing disruptive arousals andfaster depletion of fat reserves.It is better for dormice to be cool; even hard frosts are not a serious danger to them.

Juvenile dormice weighing less than 15 g in late Octobergenerally do not survive thewinter. Their removal tocaptivity therefore does notsignificantly affect the wildpopulation, but is illegal unlesslicensed by English Nature.Licences may be granted forapproved conservation projects,but these need to be long-termand part of an integrated national programme fordormouse conservation.

7.2 Reintroductions andtranslocations

English Nature, in partnershipwith the Mammals Trust UK, is committed to re-establishingdormice in counties where they have become extinct.Extinction often resulted frompast problems that have now

ceased and extensive areas ofpotentially suitable habitat areavailable but lack dormicebecause they are unable torecolonise naturally. There isalso a desire to reinforcepopulations in areas wheredormouse sites are few and widely scattered as a result ofhabitat fragmentation. In suchcases, filling in gaps betweenexisting relict populations mayhelp to conserve the species as awhole by reducing the isolation of surviving groups.

Sometimes there is a need tomove dormice (for example, froma large development site or roadwidening scheme) and releasethem elsewhere. In such cases, it is strongly advised that, wheretranslocation is likely to beneeded, liaison with the CommonDormouse Captive BreedersGroup and English Nature islikely to be mutually beneficial.Where translocation is needed toremove dormice from adevelopment site, it is generallybetter to release animals intonearby suitable sites, or to areaswhere the habitat has beenenhanced in advance (forexample, by appropriateplanting). Nest boxes should alsobe in place, preferably at adensity of about 20 to 25 per ha.

Dormice are nocturnal animals with specialised requirements and should not be kept as pets.

Taking them from the wild for this purpose is illegal. A specialist consortium of zoos and

volunteers (the Common Dormouse Captive Breeders Group) maintains a captive population of

dormice, based on dormice rescued from cats and animals taken (under licence) from the wild

that would otherwise probably have died. The purpose of this captive population is to maintain

the animals in sufficiently large numbers to supply dormice for reintroduction projects intended

to supplement fragmented wild populations.

7.1 Captive breeding

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Selecting suitable sites for releasesto take place is time consuming.Sites need to have more than 20 haof suitable habitat, yet be currentlyfree of dormice in order to avoidterritorial conflicts and excessivepressure on food and nestingresources. The aim of releasingdormice must be to establish aviable population, not just ‘let themgo’. It is therefore important not torelease dormice in circumstanceswhere the majority will soon die.It is also potentially wasteful to‘reintroduce’ dormice to siteswhere they are already present andmay occur at a low density fornatural reasons. Where dormiceare already present resident malesmay kill released individuals, sochecks should be made forevidence of dormice being presentbefore plans proceed.

An essential part of preparatorywork is to carry out a disease risk analysis, particularly to detectalien (non-native) parasites in thedonor population. Theintroduction of alien parasites intothe native population of dormicecould cause an epidemic. At thisstage it is also important todetermine the potential effect ofnative dormice and their parasiteson the reintroduced individuals’health. If the conservation benefitsof a reintroduction are consideredto outweigh the disease risks, andthe reintroduction goes ahead, it isimportant to carry out a healthsurveillance of the reintroducedanimals, before and after release, tosafeguard their welfare. Diseaserisk analysis and health surveillance

for the national reintroductionprojects is carried out by theZoological Society of London,Regents Park, London, NW1 4RY.

Release of small numbers ofanimals carries a disproportionaterisk of failure. Translocationsshould therefore be based onreleasing groups of 30 or moreanimals. Released animals shouldweigh at least 16 g, preferably morethan 20 g, or they may haveinsufficient reserves to survive thefirst few days. Studies have shownthat captive-bred animals have alower survival potential whenreleased into the wild. However,they still play a vital part inreintroductions, when properly

Figure 18 Pre-releasecage attached to a tree.

Dormice intended for release are installed here

and acclimated to the site for about ten days before

being allowed to escape through a small hole in the

top. They can then return at will to use their nest box

inside. Extra food should besupplied in the opened

cage for at least a month afterwards, replenished regularlythrough the plastic access pipe at

the side of the cage.

Sites suitable for releasing dormice have the following features:

1 A diverse, unshaded and productive understorey, preferably dominated by hazel.

2 A variety of other supportive tree and shrub species (see Table 1).

3 At least 20 ha of suitable habitat, less only if the site is well connected to other woods.

4 At least 100 nest boxes in place, with appropriate monitoring arrangements.

5 A commitment to suitable site management in the future.

managed. It is often difficult toobtain sufficient wild-caughtdormice to form a viable releasegroup. If small numbers of dormiceare obtained (for example, as part ofa rescue operation) it is better tocontact the Captive Breeders Groupand arrange for them to become partof a larger release group.

It is pointless to release dormiceunless the habitat is suitable andlarge enough. It is also importantthat the cause of their originalextinction has been removed andthat a secure commitment has beenobtained to ensure that future habitatmanagement will favour dormice.Site preparation should includeprovision of at least 100 nest boxes.These will be needed not just to aidthe dormice, but also to allow futuremonitoring of numbers and success.


Release without provision formonitoring and proper habitatpreparation is irresponsible.

Dormice have complex ecologicalrequirements. Studies have shownthat if they are simply let go, themajority will disperse and/or starveto death within a few days. Theyrequire support after release. Forthis reason, they should first beestablished in pre-release cages.This allows them to becomeaccustomed to the site beforerelease. Cages made from weldedmesh should be attached to one ofthe poles of a mature hazel. Eachshould contain two or three nestboxes and plenty of fresh hazelbranches to provide shelter andallow the animals to climb about.Ideally, each cage should contain amale and female pair of dormice that have been familiar with each other for several weeks, as theyare more likely to stay together. Itis also possible to use singledormice, a mother and litter ofyoung, or one male with twofemales. Release cages containingadult males must be 100 m apart orfatal aggression may result when theanimals are released. Cages withonly females should be sited in-between male-only cages. Overall,the aim should be to release similarnumbers of males and females.

The timing of releases is critical.If animals are let go late in thesummer there will be plenty offood for them, but any offspringthey produce will have too littletime to fatten up for the oncomingwinter. This is important becausethe production of a large number ofyoung in the first year ofreintroduction is critical to itssuccess. Releases should thereforetake place no later than early July.Animals should be introduced intothe pre-release cages in mid-tolate-June and kept there for at least10 days to become accustomed totheir new surroundings. They mustbe fed fresh fruit like apple daily,with a constant supply of biscuit,peanuts and sunflower seeds. Iffood is not eaten, the cage should

be opened and the health of theanimals checked. Releases shouldbe made during fine weather,avoiding cold periods, by making asmall opening (about 3 cm) in thecage roof. This will allow thedormice to come and go as theyplease. The aperture should besmall enough (about 5 cm x 5 cmmaximum) to exclude squirrels andbirds that will otherwise raid thecages for food.

Food must be continuously availablein the cages, with the fruit reneweddaily, for at least 2 weeks. Afterthat, the fruit may be slowlywithdrawn. This supplementaryfood is important during theestablishment period. It also helpsmaintain body condition in thefemales so that they cansuccessfully produce and rear their

young. Moreover, feeding helps tomaintain a cohesive population;without it dispersal is likely,reducing the probability of breeding.It is very important that the newpopulation should breed and buildup its numbers as soon as possible.Once the natural fruit and nut cropis ripe (usually late August), allartificial feeding should cease inorder to encourage the developmentof natural feeding habits.

By late August, the animals should be independent and theircages can be removed, leaving the nest box in place. All the nest boxes should be checked inSeptember and October to countand weigh the dormice and to notenumbers of young. After this theyshould be left alone until May thefollowing year.

Checklist of things to resolve before releasing dormice

1 Are there dormice already present? If so, why are more being

released?

2 Is the site big enough to support a viable population in the long term

(that is, more than 20 ha).

3 Is the habitat and its management suitable? If so, why are dormice

not present already?

4 Where are the dormice coming from; are there sufficient numbers?

5 Have relevant licences and permissions been obtained?

6 Are the necessary 100 plus nest boxes available, with people to put

them up?

7 Are pre-release cages available and ready to put up?

8 Is there a team of people organised to ensure daily feeding at the

crucial time?

9 Is there someone who will check the nest boxes regularly, now and in

future?

10 Have English Nature or the Countryside Council for Wales, and the

relevant County Wildlife Trust been informed?

11 Have arrangements been made (and licences obtained) for permanent

marking, where long term monitoring of individuals is part of the

project plan?

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There should be monthlymonitoring of the nest boxes toobserve progress. Details of therelease should be deposited withEnglish Nature and the localWildlife Trust. This is to ensurethat future conservationists willknow when and where the animals were introduced and also what happened to them.Such records are important, even in the case of failure, to aid future conservation management.At present, no licence is necessaryto release dormice (although thismay change in the future), but alicence is needed to checkdormouse nest boxes.

7.3 Progress so far

To date, more than a dozensuccessful reintroductions havetaken place (see Bright & Morris2002, for a summary up until2000). Several additionaltranslocations have also takenplace to mitigate the impact ofdevelopment projects, especiallyroad construction.

Successful reintroductioncomprises two phases:establishment (when a populationbecomes self-sustaining) andspread (when population size anddistribution increase sufficiently toescape the high probability ofchance extinction to which smallpopulations are vulnerable). Likethe majority of speciesreintroductions, dormouse releaseshave taken place over small areasand involved a small founderpopulation. Spread is therefore avital component of successfultranslocation, ensuring that aviable population is established,capable of persisting over time.However, spread (of dormice orother mammal species) has rarelybeen measured followingreintroductions or translocations.

An assessment of the success ofthe 11 dormouse reintroductionscarried out between 1993 and2002 has been made by Sanderson(2004). In order to measure

dispersal, over 1000 dormousenest tubes were set up around thesix earliest reintroduction sites stillsupporting dormouse populations.Grids of nest tubes were placed atdistances of 500 m, 1000 m and1500 m from the sites of theoriginal reintroductions. Checkingfor dormice in September andOctober 2002 revealed that mostof the earlier reintroductions hadresulted in both establishment andspread of the population.

The number of dormice livingaway from their release site waspositively related to the size of thefounder population: the moreanimals released, the better theyhad spread. Habitat connectionswith other woods and hedges were also important. Single large woods providing highquality habitat rather than smaller, connected ones, alsoencouraged rapid spread.Dormice were able to coloniseconnected woods, but spreadoccurred more slowly betweenwoods than within woods.

It also seems that, althoughjuveniles may colonise new sitesquite readily, it takes some yearsbefore a permanent population,

including adults, becomesestablished. Nevertheless, four of the original reintroductions had reached the spread phase inless than 10 years, and three haddeveloped satellite sites nearby,with populations of more than five dormice per hectare.

Using VORTEX (populationmodelling software), and assuminga founder population of 30 animals, the probability ofextinction within 100 years wasless than 30 per cent in goodhabitat, but over 45 per cent inpoorer habitat. This emphasisesthe vulnerability of singledormouse populations andhighlights why they have oftendisappeared from small isolatedsites. When catastrophes (such astemporary, but severe, reduction inbreeding success) were included inthe population model, thelikelihood of extinction was almost50 per cent, even in the bestconditions. Population modellingalso suggested that reintroductionsare more likely to create a quicklyspreading population if they have alarge founder population,preferably more than 40 animals.However, larger numbers may belogistically impractical.

Criteria of success

True success will only be achieved when the new dormouse colony is self-sustaining in the long term. Often the notional target is set of having asecure population still present in 100 years time, in the meantime othershort term milestones should be passed:

Stage 1 Release should be accomplished by July, with animals returning to feed in their cages, even if they do not live inthem all the time.

Stage 2 There should be young born at the new site, preferably bySeptember of the first year.

Stage 3 At least some animals should still be alive after the first winter,present in the nest boxes in May of year 2.

Stage 4 The second summer should see the birth of second generationyoung (i.e. born to females who themselves were born at thesite), but this will be difficult to demonstrate unless the originalreleased animals had been permanently marked.

Stage 5 The third or fourth summer should see more adults presentthan were originally released (that is, survival should by nowexceed losses).


8 The National Dormouse MonitoringProgramme

8.1 Monitoring Dormice at National and Regional Level

The year-by-year results ofmonitoring dormouse populationsare reported to contributors via The Dormouse Monitor, circulatedtwice a year and also freelyavailable on the MTUK and PTES websites. However, thenumber of dormice recorded innest boxes fluctuates in response tofactors such as the weather, soalthough short-term results may bevery interesting, they do notnecessarily indicate real long-termtrends. Short-term variability caneasily mask real changes andcompromises attempts tosubstantiate statistically any trendsthat appear to be happening.Fortunately, we now have long setsof data from nearly 100 sites, allowing an analysis (byFiona Sanderson) to assess whetherthe system works or not, and whatmight be learned as a consequence.

The key question is whether theNDMP can detect a populationchange of conservation significance,or whether more sites need to beadded to the scheme to make itreliable. The ‘red alert’ declinefigure used in bird monitoring in the UK is 50 per cent change over25 years, equivalent to about 27 per cent over 10 years. It seemsthat, with 100 monitoring sites, theNDMP can easily detect a national

The National Dormouse Monitoring Programme (NDMP) collates data from more than 200 key sites

in various parts of the country. The aim is to collect long-term data about abundance, annual

variation in timing and success of breeding, and also population density in different habitats and

geographical areas. A newsletter The Dormouse Monitor is distributed to participants. Recording

forms are available and new sites qualify for addition to the scheme provided they have at least

50 nest boxes in place and someone willing to monitor them regularly. Submission of data to the

NDMP is a standard condition of English Nature licences to inspect nest boxes. The NDMP is

administered by the People’s Trust for Endangered Species (PTES) and the Mammals Trust UK

(MTUK); details are available from English Nature or the MTUK.

Figure 19 Population trends from the National Dormouse MonitoringProgramme. The index of abundance shows changes since a 1993 baseline.There appears to have been a downward trend in the north of England andparts of Wales, but dormice seem to be holding their own in the south.

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decline of about this level. We mayneed more sites in particular regions(especially in the north) to detectmore localised changes, but theNDMP is effective enough to detectsignificant national trends.

The next question is whether therereally has been any trend indormouse abundance over the lastfew years. In fact, there have beenmajor changes in abundance, but thetrend differs in different parts of thecountry. Data from 83 NDMP sitessuggest a national decline of about19 per cent in dormouse abundancebetween 1991 and 2000 (Sandersonand Bright, in preparation).Populations in northern England havedeclined much more (by 40 per centbetween 1993 and 2000), while insouthern England the total populationappears to be relatively stable.

Dormice are extremely sensitive tothe weather, and as habitatspecialists, they are also likely tobe sensitive to changes in thequality of their habitat. TheNational Dormouse MonitoringProgramme allows analysis of thelikely effects of theseenvironmental factors on dormouseabundance. Weather can affectpopulations in different ways atdifferent times of year. Dormiceneed cold, dry winters to hibernatesuccessfully and if temperaturesrise suddenly in winter, they wakeup, but risk starvation as there is nofood available. However, insummer, dormice need warm, dryconditions, both to encouragefruiting and flowering of foodplants, and to keep them awake andbreeding instead of cold and torpid.

In fact the monitoring dataconfirms that weather affectsdormice at most times of year.Dormouse numbers are higher inyears following a cold, dry winteror warm spring. The number ofyoung dormice born per female ishigher in hot dry summers than atother times. However, warmsprings and hot summers only

benefit populations in woods thathave food plants (such as oaktrees), which support the largenumbers of insects that providefood early in the breeding season.Hot spring and summer weatherdoes not have the same impact atsites where dormice breed later inthe year. This means that the sameweather has different effects upondifferent populations. Unlikedormice in continental Europe,from Lithuania to Italy, Britishdormice usually only raise a singlelitter each year. Their breedingsuccess is therefore very vulnerableto cold, wet weather occurring atpeak breeding times, which cansend them into torpor and alsoreduce the fruiting and floweringof their food plants. Studies at theUniversity of East Anglia suggestthat there is an ongoing increase inair temperature and winter rainfallin Britain, with a marked increasein north-west England. There isalso an increase in spring days withhigh rainfall in all regions wheredormice occur except parts ofsouth-east England. This does notbode well for dormice and changesin weather patterns may explain thechanges already seen in dormousenumbers, both regionally and overthe past century.

Although summer weather seems tobe getting hotter, the NDMPsuggests that there is no significantincrease in the numbers of dormicebeing born. At many sites, thenumber of juveniles born perfemale has actually declined since1993. The decline may be due todecreased productivity, and theenvironmental factor causing it maybe habitat quality. Dormice aresensitive to small changes in theirhabitat and there have been majorchanges in our woods that arelikely to have been detrimental todormouse conservation. Forexample, increased deerpopulations and the ingress ofsheep into ancient woods leads tothe browsing of some importantfood plants and the trampling of

others. Changes in woodlandmanagement, such as coppicing,also impact on dormice. Targetedmanagement could help to reversethese effects and conservedormouse populations. UsingNDMP data for a populationmodelling study showed thatretaining a high proportion of mid-aged hazel coppice (between 6and 25 years), and increasing theproportion of the site containing ofmid-ages coppice from 10 per centto 50 per cent could increasedormouse populations by over 50per cent, but only in woods wherethe hazel had previously stoppedfruiting abundantly. Where theexisting hazel was still fruitingwell, coppice management wasrelated to a (possibly temporary)decrease in population size, perhapsbecause coppicing, howevernecessary, is a form of disturbance.

So dormouse populations areextremely sensitive to both climateand habitat quality and also to theinteraction between them. Theyare therefore one of the speciesthat we particularly need tomonitor in a changing world.

8.2 Other recording schemes.

Most counties now have a wildlifedata recording system as part ofthe National Biodiversity Network(NBN), usually based either withthe local Wildlife Trust or theLocal Authority. The aim is tocollect locality data for plants andanimals, so that their distributionis properly known. In addition,there is a Dormouse Site Inventoryheld by English Nature butavailable via the NBN(www.searchnbn.net). Thepurpose of this is to make it easier to decide where newsurveys are needed and whichsites are at risk when newdevelopments are proposed. It isimportant that translocations andfresh surveys should input data toone or more of these systems tokeep them up to date.


A major review of the UK BAP isbeing carried out in 2005-6.Although the targets for thedormouse will be more preciselydefined, it seems likely that it willremain a priority species.

9.2 Progress with thenational action plan

The national action plan, publishedin 1994, which built on conservationinitiatives already in progress,identified a number of actions thatwould help to deliver the targets.Substantial progress has been madein delivering many of these over thepast decade and the followingparagraphs summarise progress todate on the most significant actions.

9.2.1 Site safeguard andmanagement

A national inventory of dormousesites has been produced,incorporating results from two‘Great Nut Hunt’ surveys as wellas many other recent records.These data are now availablethrough the National BiodiversityNetwork (www.searchnbn.net).The first edition of this dormouseconservation handbook, publishedin 1996, gave management adviceto landowners, which has beensubstantially expanded in thissecond edition. Research ondormice in hedgerows hasprovided clear guidance on

appropriate management and thishas now been incorporated intoagri-environment schemes.

9.2.2 Species management andprotection

The objective of reintroducingdormice to five counties andreinforcing populations in threemore has been exceeded, with 14reintroductions in 11 counties by2005. Most dormice for thesereintroductions have been suppliedby the Common Dormouse Captive Breeders Group, which hasdeveloped considerable expertise in maintaining and breeding thespecies. A recent review of 11 ofthese reintroductions (Sanderson2004) demonstrated a high degreeof success.

9.2.3 Advisory

As well as producing the advisoryhandbook, numerous courses havebeen held for foresters, ecologicalconsultants and conservation staffon dormouse conservationtechniques.

9.2.4 Research and monitoring

A long-term programme of researchhas continued throughout the lasttwo decades, with particularemphasis on understanding theneeds of dormice in hedgerows andthe impact of woodland restoration

on dormouse populations.This research has been focused on supporting management advice and identifying areas where improvements toconservation actions could bemade. Studies have also beenundertaken to learn more about theecology of dormice in coniferwoodland, again with a view toproviding practical managementguidance, particularly in connectionwith clearance operations.

The use of ‘green bridges’ bydormice should be investigatedwith a view to providing advice ontheir likely effectiveness inrelation to width of obstacles(such as roads) to be bridged.

The development of the NationalDormouse Monitoring Programme,described in Chapter 8 has been asignificant success, with 200 sitesand 11,000 boxes now beingmonitored annually by volunteers.A recent review of this monitoringsystem confirmed that it coulddetect changes in the nationaldormouse population with adequatesensitivity to meet the requirementsof the Tracking MammalsPartnership. This system, based on a national series of Key Sites,has been supplemented by twopublic-participation Great NutHunts, which have resulted in the discovery of many new sitesfor dormice.

9 Conservation achievements andpriorities

9.1 The UK Biodiversity Action Plan

The dormouse is a priority species in the UK Biodiversity Action Plan (UKBAP) and has an

individual Species Action Plan. Joint Lead Partners for this plan are English Nature and The

Wildlife Trusts. The plan’s current targets are to maintain and enhance existing dormouse

populations in all counties and to re-establish self-sustaining populations where they have been

lost. Other dormouse action plans have been produced at local, county and regional scales,

usually as part of the Local Biodiversity Action Plan (LBAP) process. Details of both the national

species action plan and local action plans can be found at www.ukbap.org.uk

64

9.2.5 Communications andpublicity

Many of the actions described inthe preceding paragraphs, mostnotably the two Great Nut Hunts,have resulted in the dormousehaving a very high public profile,with extensive coverage in thePress. The first nut hunt gainedmore publicity for English Naturethan any of its othercontemporary projects and thereintroduction of dormice toCheshire drew much attention tothe Cheshire Wildlife Trust, eventhough the site was secret andcould not be visited by the public.It has since been the focus of abroader approach to wildlifeconservation in the vicinity,involving many partners.Nationally, the dormouse‘awareness’ of landowners andplanners has also increased.

9.3 Priorities for the nextdecade

� Maintain surveillance throughthe National DormouseMonitoring Programme(NDMP); repeat the Great NutHunt at intervals.

� Improve and extend thenational inventory of dormouse sites. Ensureavailability of data through the National BiodiversityNetwork (NBN).

� Continue research on theecology of dormice,particularly in the marginaluplands; deliver managementadvice.

� Undertake studies tounderstand the impact ofweather and climate change.

� Review the future of thereintroduction programme andassociated captive breedingschemes.

� Encourage population expansionfrom reintroduction sites;encourage and develop habitatlinkages in the countryside.

� Encourage the targeting ofgrants to include dormousehabitat restoration andmanagement.

� Publish information aboutdormice in conifers withappropriate actions to be taken.

� Improve management,mitigation and best practiceadvice in relation todevelopment and forestry.Publish improved guidance asit becomes available.


10 Organisations & contacts10.1 English Nature

English Nature is thegovernment’s statutory advisor onnature conservation. It has a widerange of functions including:

� Provision of advice to LocalPlanning Authorities onEuropean protected speciesissues, including protectedspecies policies andconsultations on planningapplications where dormice are thought to occur.

� Provision of general advice todevelopers, consultants andothers on protected species.

� Issuing licences for scientific andeducational work on dormice.

� Advising Defra over licencesapplied for under the HabitatsRegulations.

� Provision of advice involvingwildlife law enforcement.

� Statutory consultee overplanning issues affecting Sitesof Special Scientific Interest.

� Assisting with the delivery ofSpecies Action Plans forpriority species.

Note that services currentlydelivered by the RuralDevelopment Service (RDS) willbe transferred to a new Agency,Natural England, in October 2006.

In Wales, the Welsh AssemblyGovernment (CountrysideDivision) has a similar role.

10.3 Office of the DeputyPrime Minister

The ODPM has the followingroles in connection with dormiceand development:

� Producing the Government’sPlanning Policy Statement(PPS) for Local PlanningAuthorities in respect of natureconservation and speciesprotection (currently PPS9:Biodiversity and GeologicalConservation, 2005).

� The Secretary of State at theOffice of the Deputy PrimeMinister determines planningappeals, applications which are ‘called in’, local inquiries and presides over Local Plan inquiries.

Note that services currentlydelivered by English Nature will be transferred to a new Agency,Natural England, in October 2006.

In Wales, the Countryside Councilfor Wales has a similar role.

10.2 The Department forEnvironment, Food and Rural Affairs

Defra has the following roles inconnection with dormice:

� Assisting in the development ofUK wildlife legislation.

� Responsible for ensuring thatthe UK Habitats & SpeciesDirective is properlyimplemented.

� Determining licence applicationsfor activities under Regulation44(2)(e) of the 1994 HabitatsRegulations and monitoringlicence compliance. Thisservice is provided by the RDS.

� Delivering EnvironmentalStewardship. This service isprovided by the RDS.

ContactCountryside Council for Wales,

Maes y Ffynnon, Penrhosgarnedd,Bangor, Gwynedd, LL57 2DW

Tel: 0845 130 6229Website:

www.ccw.gov.uk

ContactWelsh Assembly Government,

Countryside Division,Cathays Park, Cardiff, CF10 3NQ

Tel: 029 2082 5203Website:

www.countryside.wales.gov.uk

ContactEuropean Wildlife Division,

Defra, Zone 1/08c, Temple QuayHouse, 2 The Square, Temple Quay,

Bristol, BS1 6EBTel: 0117 372 6170

Website: www.defra.gov.uk/wildlife-countryside/ewd/index.htm

European Protected SpeciesLicensing, Wildlife AdministrationUnit, RDS, Burghill Road, Bristol,

BS10 6NJTel: 0845 601 4523

Email: [email protected]

ContactPolicy Branch,

Planning Policies Division (PD1),ODPM, 4/H4 Eland House,Bressenden Place, London,

SW1E 5DUTel: 020 7944 3973

Website:www.planning.odpm.gov.uk/

ContactEnglish Nature,

Northminster House,Peterborough, PE1 1UA

Tel: 01733 455000Website:

www.english-nature.org.uk

66

10.4 Local PlanningAuthorities

Local Planning Authorities havethe following roles:

� Ensuring that protected speciesissues are taken into accountwhen determining planningapplications, as set out inPPS9. This may involverefusal, deferral, conditions or agreements.

� Ensuring that protected speciesissues are taken into account inpreparation of Local Plans,UDPs, etc.This and the above point relateto Regulation 3(4) of theConservation (Natural Habitats&c.) Regulations 1994, whichrequire authorities to haveregard to the conservation ofEuropean Protected Species.

� Raise awareness of protectedspecies in their area and, insome cases, enforce wildlifelegislation (S.25 of the Wildlife and CountrysideAct 1981).

� Advising developers aboutstatutory species protectionprovisions affecting anapplication site.

� Enforcement of planningobligations and Agreements.

10.5 Developers andenvironmental consultants

Developers and their advisor(s)share responsibility for:

� Ensuring that they provideLocal Planning Authorities withsatisfactory and accurateassessments of application sites,including surveys for dormiceif they are potentially present.

� Applying to Defra for alicence, should they judge oneto be required.

� Providing an objectiveassessment of the potentialimpact of proposed developmenton dormouse populations.

� Where necessary, designingand implementing a mitigationscheme that meets planningand licensing requirements.Specifically, such plans willensure, as far as possible, the long term future of anypopulations affected; suchschemes should employ ‘best practice’.

� Where necessary, negotiatingwith Local PlanningAuthorities a planningagreement (S106) or similar, to ensure continued support foraffected dormouse populations.In many cases, monitoring ofaffected populations aftercompletion of development.

Contact details for environmentalconsultants can be obtained froma number of sources, includingtheir professional bodies andpublished directories. Two suchdirectories are:

� The Environmental Data Services(ENDS) EnvironmentalConsultancy Directory(www.endsdirectory.com/search/)

� The Institute of Ecologists andEnvironmental Managers(IEEM) Directory(www.ieem.co.uk).

10.6 The Forestry Commission

The Forestry Commission issuesfelling licences for felling timberbut the landowner and timberfeller are responsible for workingwithin existing legislation relatingto biodiversity.

Forestry Commission grants forwoodland management areavailable, provided a commitment is made to acceptable environmentalcodes of practice as part of thescheme. Advice from the ForestryCommission must be sought toassess the need for an‘Environmental Assessment’ wherechange of land use to, or from,woodland is involved. The ForestryCommission is not normallyinvolved in matters concerned withbuilding developments.

ContactWebsite 1:

www.direct.gov.uk/Dl1/Directories/LocalCouncils/fs/en

Website 2:www.planningportal.gov.uk/engla

nd/genpub/en/

ContactThe Forestry Commission, GreatEastern House, Tenison Road,

Cambridge, CB1 2DUTel: 01223 314546

Website: www.forestry.gov.uk Email: nationaloffice.fce@

forestry.gsi.gov.uk


10.9 Local Biological RecordsCentres and the NBN

These often have usefulinformation on where dormicemight be found locally, and siteswhich are already known toharbour dormice. They canprovide such details to consultants,developers and Local PlanningAuthorities. Similarly, some localnatural history societies maycollect location data and be able toprovide a more detailed assessmentof status; some may also be willingto assist with dormouse surveys inadvance of planning applications.

Much of the information held bylocal records centres or EnglishNature is gradually being madeavailable through the NationalBiodiversity Network (NBN)gateway. For example, thenational dormouse inventorycompiled by English Nature isnow available in this way.

10.8 People’s Trust forEndangered Species and theMammals Trust UK

The People’s Trust for EndangeredSpecies (PTES) administers theNational Dormouse MonitoringProgramme and coordinatesdormouse reintroduction projects.Mammals Trust UK (MTUK), arestricted fund of the PTES,provides grant aid for theconservation of British mammals.

10.7 County Wildlife Trusts

The Wildlife Trusts Partnershipcomprises a network of 47autonomous county-based wildlifetrusts whose primary concern iswildlife conservation within theirown geographical area. TheWildlife Trusts are responsible for:

� Organising volunteer supportfor local wildlife conservation.

� Administering grant aid forwildlife support.

� Managing some local naturereserves and public openspaces.

� Providing assistance and adviceon conservation and wildlifematters, within theircapabilities and resources.

� Liaising with local authoritiesand local non-Governmentalorganisations (NGOs) tofacilitate wildlife conservation.

� Joint Lead Partner (with English Nature) for the dormouseBiodiversity Action Plan.

ContactPTES/MTUK, Cloisters House, 8 Battersea Park Rd, London,

SW8 4BG.Tel (PTES): 020 7498 4533

Website (PTES): www.ptes.orgEmail (PTES): [email protected]

Tel (MTUK): 020 7498 5262Website (MTUK): www.mtuk.org

Email (MTUK): [email protected]

ContactA list of local records centres can

be found at: Website: www.nbn-nfbr.org.uk/nbn.php

The NBN gateway is at:Website: www.searchnbn.net

ContactThe Wildlife Trusts, The Kiln,

Waterside, Mather Road, Newark,Nottinghamshire, NG24 1WT

Tel: 0870 036 7711Website: www.wildlifetrusts.org

Email: [email protected]

68

10.10 The Mammal Society

The Mammal Society wasinvolved with much of the originalresearch on dormice, including thefirst survey, and this researchcontinues, mainly through its localgroups in the south-west. Inaddition to providing training forconsultants and applicants fordormouse handling licences, TheSociety supplies nest tubes andhas published a useful booklet ondormouse biology.

10.12 Other organisations

Enforcement of most relevantlegislation is carried out by thePolice, and in most forces there is now a Wildlife Crime Officer(WCO) who will assist (seewww.police.uk). A list of policeWCOs is also available from theRSPB Investigations Section (Tel: 01767 680551).

10.11 Common DormouseCaptive Breeders Group(CDCBG)

The CDCBG coordinates the captivebreeding programme that suppliesanimals for reintroductions. Theseare coordinated by the People’sTrust for Endangered Species.

ContactThe Mammal Society, 2B Inworth

St, London, SW11 3EPTel: 0207 350 2200

Website: www.mammal.org.uk Email: [email protected]

ContactThe Common Dormouse Captive

Breeders Group, c/o Paignton Zoo Environmental Park

Totnes Road, Paignton, Devon, TQ4 7EU Tel: 01803 697500


11.1 Developing NationalCycle Route 45 in The SevernValley, Shropshire

Contributed by Cathy Turtle

Background

National Cycle Route number 45is being built within woodlandsand scrub along the Severn Valleybetween Bridgnorth and Bewdley.Surveys have confirmed dormiceare present in the woodlands.There are two confirmedpopulations divided by an activesteam railway and, moresignificantly, the River Severn. It was assumed that all potential

habitats affected by the schemecould support dormice.

Description of works

The cycle route consists of ahardcore base with a geo-textileliner. Where the slopes are steeppiling has been installed. Theconstruction machinery requiredaccess from several areas that crossthe railway line. In parallel to this,the bridge that joins Highley toAlveley needed to be replaced,requiring a large working area nearthe bridge and further access routesthrough the Severn Valley CountryPark for more machinery.

Features of importance todormice

The habitats of value affected by thecycle route include nativebroadleaved woodland, diversescrub, including some bracken, andareas of recently planted native treesand shrubs within the country park.The railway verges are managed bysmall areas of coppicing over a longtime period, which has created someexcellent habitat.

The secondary woodland withinthe Severn Valley Country Park is

11 Case studies in development andforestry

It is too early to measure the

effectiveness of recent

attempts to mitigate the

impacts of development.

Similarly it is too soon to see

the effects of changes in

forestry practice.

Nevertheless, two case

studies are described below;

further studies are welcome.

Timetable & execution

Year 1

July Site clearance with hand-searching for nests prior to strimming

August Further checks for birds prior to clearing remaining areas. Nest box and tube installation

October Supervision of site clearance for bridge works on the eastern side of the river. Nest boxand tube installation

December Completion of cycle route

Year 2

January Start of bridge works

June & October Monitoring of boxes and tubes

December Bridge completion

young but has a continuouscanopy cover. This woodland isonly tentatively connected to theancient woodland site, withdormice confirmed on the easternside of the River Severn as thetrees and shrubs are too immatureto provide full cover at any level.

Project approach

Due to project timing, driven byfunding, the clearance work had tostart in July. The line of the route,soil storage and working areas werehand searched for both dormouseand bird nests. Where nests werefound warning tape was installed toprevent disturbance until the birdshad fledged. No dormouse nestswere found but they would alsohave been left until the young hadleft the nest. The site was then‘strimmed’ to the ground to preventfurther nesting, and vegetationcleared to dissuade dormice fromhibernating in the area. All potentialshelter areas such as wood piles anddebris were dismantled by hand andremoved to locations off-route.Nest boxes were installed inwoodland areas off route and nesttubes were put in place along thehedgerows and fences that connectareas of value for dormice.

70

Once work was completed, thesoil storage and working areaswere re-planted with species tofavour dormice. Several hazelglades were created. These wereplanted within the even-agedsecondary woodland in theCountry Park to increase diversity.

Where machinery has broken thelinks in the canopy, branches will be tied together overhead in year 2 (see below) to bridge the route at several places alongthe access tracks.

Monitoring

The site will be monitored for oneyear after completion. This willhopefully confirm the continuedpresence of dormice within thearea and increase ourunderstanding of the twopopulations.

11.2 Reconstructing a roadjunction

Contributed by Paul Chanin

Background

The reconstruction of this roadjunction involved the realignment

of 80 m of hedge, it beingpreferable to move, rather than replace, the hedgerow. The hedge was diverse, had a lot of mature hazel and wasunmanaged. It was more than 4 m wide and high. Apreliminary survey (looking for hazel nuts) showed thatdormice were present in nearbyhedges, although not in the one to be moved.

Project approach

� Install nest boxes in hedges oneither side of the one to bemoved.

� Carry out metre by metresearch for nests within thehedge.

� ‘Coppice’ hedgerow shrubs (in summer).

� Move hedge during winter to maximise tree and shrubsurvival.

Results

This project was carried out beforethe need for licensing wasintroduced, so there was no

requirement for a follow-up.Four years later the transplantedhedge is just beginning to recoveras most shrubs and trees failed tosurvive the move. Another hedgeon the other side of the road wasmoved as part of the same roadscheme and survived much better,perhaps because it was not cut soclose to the ground. Clearlybotanical advice should be soughtbefore attempting hedgetranslocations.

Lessons

� Dormice do breed in hedges.

� Nest boxes can be used as ameans of encouraging dormiceout of threatened habitat.

� You may still get some nests inthe area to be destroyed andneed to make sure thatclearance is done with clearguidelines on what to look for.

� Dormouse nests are easier tofind while clearing a hedgethan by visual survey.

� Good guidance is required onhedge moving and other formsof mitigation.

Timetable & execution

April Nest boxes installed

July Dormouse nest found in one box

September Four boxes found with nests. Two adult dormice present in one of these, five juveniles inanother

October Hedge surveyed from inside looking outwards (so that nests would be seen against thelight) none found.Trees and shrubs coppiced following on-the-spot briefing of contractors on dormousenests and how to recognise them.Two summer nests found during clearance, both very low to ground (c 30 cm) at the edgeof the hedge growth, in bramble and small blackthorn. No dormice in either. One old hibernation nest found under small flat stone ca 2m from midline of hedge

Winter Hedge moved


Anderson, P. & Groutage, P. 2003 Habitat translocation – a best practice guide (C600). Construction IndustryResearch and Information Association.

Battersby, J. (Ed.) & Tracking Mammals Partnership. 2005. UK mammals: species status and populationtrends. First report by the Tracking Mammals Partnership. JNCC/Tracking Mammals Partnership,Peterborough.

Bright, P.W. 2000. Status and woodland requirements of the dormouse in Wales. CCW Science Report 406.Bangor: Countryside Council for Wales.

Bright, P. & MacPherson, D. 2002. Hedgerow management, dormice and biodiversity. English Nature ResearchReport No. 454.

Bright, P. & Morris, P. 1989. A practical guide to dormouse conservation. Occasional Publication no.11.London: The Mammal Society.

Bright, P. & Morris, P. 1990. Habitat requirements of dormice (Muscardinus avellanarius) in relation towoodland management in Southwest England. Biological Conservation. 54: 307–326

Bright, P.W. & Morris, P.A. 1991. Ranging and nesting behaviour of the dormouse Muscardinus avellanarius,in diverse low-growing woodland. Journal of Zoology. 224 177–190

Bright, P.W. & Morris, P.A. 1992. Ranging and nesting behaviour of the dormouse (Muscardinus avellanarius)in coppice-with-standards woodland. Journal of Zoology. 226 589–600

Bright, P.W. & Morris, P.A. 1993. Foraging behaviour of dormice Muscardinus avellanarius in two contrastinghabitats. Journal of Zoology. 69–85

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Bright, P.W. & Morris, P.A. 1994. Animal translocation for conservation: performance of dormice in relation to release methods, origin and season. Journal of Applied Ecology. 31: 699–708

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Nest box suppliers

Kingslake Resources Ltd, Bolton Farm, Lyonshall, Kington, Herefordshire, HR5 3JYTel: 01544 340657Website: www.nestbox.co.uk

Jamie Wood Ltd, 1 Green Street, Eastbourne, East Sussex, BN21 1QNTel: 01323 727291Website: www.birdtables.com

Alana Ecology, The Old Primary School, Church Street, Bishop's Castle, Shropshire , SY9 5AE Tel: 01588 630173Website: www.alanaecology.com

CJ Wild Bird Foods Ltd, The Rea, Upton Magna, Shrewsbury, SY4 4URFreephone: 0800 7312820Tel: 01743 709545Website: www.birdfood.co.uk

Dormouse nest tubes are available from The Mammal Society. Dormouse nest boxes are

available from many sources. Some of the larger suppliers are listed below, but this list is

certainly not exhaustive:

Top: Dormouse-friendly underpass/P. ChaninMiddle left: Green bridge/P. MorrisMiddle Right: Hazel nut opened by dormouse/J. NortonBottom: Dormouse nest-tube/P.Morris

English Nature, the RuralDevelopment Service and theCountryside Agency. Working in partnership to conserve and enhance our landscapes and natural environment, to promotecountryside access and recreation as well as public well-being, now and for future generations.

This is one of a range ofpublications published by: External Relations TeamEnglish NatureNorthminster HousePeterborough PE1 1UA

www.english-nature.org.uk

© English Nature 2006

Printed on Evolution Satin, 75% recycled post-consumer wastepaper, elemental chlorine free.

ISBN 1 85716 219 6

Catalogue code IN2.9

Designed and printed by statusdesign.co.uk, 2.5M.

Front cover photographs:Top left: Severn Valley cycle route.C. Turtle Middle left: Dormouse nest tube.P. Morris Bottom left: Hazel nut opened by dormouse.J. NortonMain: Dormouse in hazel. P. Morris

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