People’s Trust for Endangered Species, 3 Cloisters House, 8 Battersea Park Road, London SW84BGRegistered charity no 274206

Ecology of the hazel dormouse

Cheeky Chappie Makes An Appearance In A Fenland Garden Helping Himself To Food!

November 2009

• Wood mouse• Yellow neck

mouse• Harvest mouse• House mouse• Field vole• Bank vole• Pygmy shrew• Common shrew• Water shrew• Hazel dormouse

Family MuridaeOver 700 species including mice, rats and gerbils

• Scaled tails• Hop, climb or run• Either herbivores or

omnivores• Breed frequently• Large litters• Short-lived

• Furred tails• Generally arboreal • Nocturnal• Omnivores; lack a caecum• Breed once or twice a year• Average litter of 4• Long lived• Hibernate

Family Gliridae28 species of dormice

Order: Rodentia

Class: Mammalia

European Species

• Hazel dormouse – Muscardinus avellanarius– European status: Least concern, Pop. trend: unknown

• Fat dormouse – Glis glis– European status: Least concern, Pop. trend: unknown

• Garden dormouse – Eliomys quercinus– European status: Near threatened, Pop. trend: decreasing

• Forest dormouse - Dryomys nitedula– European status: Least concern, Pop. trend: stable

• Mouse tailed dormouse - Myomimus roachi– European status: Endangered, Pop. trend: decreasing

www.iucnredlist.org (2011)

What’s in a name?

• Common or Hazel dormouseMuscardinus avellanarius

Mus – small brown animalScardinus – young edible dormouseavellanarius – from hazelDormir – from french ‘to sleep’

• Fat or Edible dormouseGlis glis

Glisere – latin ‘to grow’

Fat dormouse

• Non native• Released 1902• Size of small

squirrel• Life cycle

linked to beech • ‘Seven sleeper’

Hazel dormouse• Native species• Adult size: 50mm body,

wt 18-30+ g• Furry tail• Sandy coat develops• Large black eyes• Pads on feet• Double-jointed hind

ankles

May

Apr

Mar

Feb

JanDec

Nov

Oct

Sept

Aug

JulyJune

Hibernating

Hibernating?

Occasional arousals

Frequent arousals

Fully active

Short periods of

activity

Breeding Young born

Young foraging

Second brood?

Fattening up for winter

The hazel dormouse year

JanFeb

Mar

Apr

May

June

JulyAug

Sept

Oct

Nov

DecHibernating

Hibernating?

Occasional arousals

Frequent arousals

Fully active

Short periods of

activity

Breeding

Young bornYoung foraging

Second brood?

Fattening up for winter

The hazel dormouse year

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

0

20

40

60

80

100

120

140

160

180

200

April

May

June

July

August

Sept

Oct

Nov

AprilMayJuneJulyAugustSeptOctNov

Weight (grams)

Freq

uenc

y

2010 Dormouse weight distribution by month, adjusted by number of NDMP sites, where dormice were recorded.

Torpor and hibernation• Latin – hiberna for

winter• Hibernation – longer

than 24hrs• Torpor – less than

24hrs• Hibernate due to lack

of food in winter• Torpor due to

inclement weather

Hibernation

• Minimum weight 15-18g• November – April• Hibernate in nests on

ground; moist, even temperature

• Coppice stools, log piles, leaf litter

• May wake/move

Torpor

• Occurs in active period

• In nest boxes – with and without nests

• Once disturbed will wake

• 20mins to full activity

Hazel dormouse diet

• Sequential feeders• Lack caecum • Nectar, pollen, seeds,

fruit, nuts, invertebrates

• Food diversity needs to be within home range

Dormouse food requirements

Honeysuckle

Bramble

Hawthorn

Sycamore

Wayfaring

Elder

Dogwood

Yew

Hazel

Buckthorn

Blackthorn

Ash

Oak

Birch

May June July August Sept Oct

Nests and breeding• Range of distinctive

nests• Breeding nest

woven covered with green leaves

• Honeysuckle strips and other local material

• Usually more than one nest

Dormouse breeding

• Males solitary• First litters late May• 4-6 young with

distinctive stages• Occasional crèches• May have second litter• Population ‘boom’ in

Sept/Oct

The ages of Hazel dormice

Stage Approx. ageApprox.weight

Coat colour

Pinks 0 – 6 days 1 – 2.5g Pink

Grey eyes closed6 – 16 days 2.5 – 6g Grey

Eyes open 16 – 28 days 6 – 10g Grey or brown

Juvenile (before first hibernation)

28+ days plus 10g plus Grey/sandy

Adult (after first hibernation)

8-12 months plus 12g plus Sandy

Dormouse home range

• Adult male home range about 0.75 ha Adult female range smaller

• Distance travelled a from nest– Male 70m (Bright and Morris 1994)

– Female 50m (Bright and Morris 1991)

– Dispersing juvenile 376m (Wilder Wych 2011)

Dormouse population densitySpecies Habitat Mean Spring

density

DormouseOptimal – diverse wood with abundant, vigorous understory

4 to 6 adults

Dormouse Oak woodland with hazel 2 adults

Dormouse Scrub unknown

Dormouse Conifer woodland 1 to 3 adults

Dormouse Hedgerow 1.3 adults

Wood mouse Deciduous woodland 40 plus

Bank vole Deciduous woodland 100 plus

Dormouse predators• Badger• Wild boar• Cats

• Owls• Grey squirrel• Stoats, weasels

Between 40 – 70% of dormice die in hibernation(Juskaitis 1977)

Dormouse activity • Adapted for arboreal lifestyle• Use aerial pathways in tree/shrub canopy• Hazel – lax growth• Bramble – scrub banks• Reluctant to cross open ground (Bright and Morris

1992)

• But non-corridor habitat not complete barrier to movement (Bright 1988, Buchner 1997, 2008)

Hazel dormouse distribution (records from 1990-2013

Dormouse habitats– Deciduous woodland with vigorous understory

• managed woodland• managed coppice woodland

– Oak wood with hazel• derelict coppice

– Scrub (connected?)– Conifer wood– Hedgerow

Dormice may be present in any wood or scrub habitat within their range

Dormouse Ecology Summary• Hibernate in nests at ground level• Arboreal when active• Exhibit torpor in inclement weather• Sequential specialist feeders• Live at low densities• Small home range• Low fecundity• Long lived

Why are dormice good?

• Key species– Plant diversity– Shrub structure

• Woodlands• Hedgerows• Scrub• Responsibility

What’s good for dormice is good for many other species

People’s Trust for Endangered Species, 3 Cloisters House, 8 Battersea Park Road, London SW8 4BG

Registered charity no 274206