MARDI Res. Bull., (1984) 12, I: (81-85)

THE NESTING HABITS OF THE MALAYSIAN WOOD RAI IN THREECOCOA CROPPING SYSTEMS

KAMAL A. KAMARUDIN*

Keywords: Malaysian wood rat, Nest sites, Nesting materials, Nest numbers, Populationcorrelation.

RINGKASAN

Artikal ini menerangkan tabiat membuat sarang bagi tikus belukar, Rauus tiomanicus (Miller) bagitiga sistem tanaman koko. Pertalian di antara bilangan sarang dengan anggaran populasi tikus juga telahdisel id ik i .

Adalah didapati bagi tanaman koko di bawah pohon lindungan Albizzia, tikus membuat sarangmereka dengan menyusun daun-daun koko ke dalam serpihan kulit kering pohon lindungan tersebut yangtelah jatuh ke atas kanopi koko atau di atas tanah. Bagi koko di bawah lindungan kelapa rendah pula,sarang dibuat d i antara ruang di pangkal pelepah dan batang kelapa. Bahan yang digunakan adalahdaun-daun kelapa dan kelopak ker ing. Daun koko juga ser ingkal i d i jadikan bahan membuat sarang. Bagitanaman koko di bawah lindungan kelapa tinggi. sarang dibina di kanopi pohon koko di atas ranting yangmana di jadikan pelantaran bagi menvokong longgokkan daun vang te lah disusun di atasnva. Bahan yangdigunakan adalah daun-daun koko,

Terdapat perta l ian yang je las di antara bi langan sarang dengan anggaran populasi t ikus bagi s istemkoko yang di tanam di bawah pohon l indungan kelapa rendah.

INTRODUCTION

The nesting habits of the Malaysianwood rat, Rattus tiomanicus (Miller) has notbeen fully investigated. MEowey (1969)described that the rat builds loose sphericalnests from green leaves, dry grasses orsimilar materials on the ground under shelteror in higher places in tree stumps or thecrown of oil palms. In cocoa, no mention ofthe rat's nest has been recorded except thatthe animal is arboreal (KnvnnuorN,

TuRrzeN BaHaRt and Aeo. RnusMnur-un,1983) .

This paper proposes to describe anddiscuss the nesting habits of the Malaysianwood rat in three different cocoa croppingsystems: 1) monocropped cocoa, 2) cocoaintercropped with dwarf coconut, and 3)cocoa intercropped with tall coconut. Theinterrelationship between nest numbers torat population estimates is also examined.

MATERIALS AND METHODS

Sungai Buloh Estate, Bukit RotanKuala Selangor and Kuala Bernam Estate,near Telok Intan were selected as the study

si tes. In the former. the cocoa are p lantedv'ith Albizzia species as shade. As for thelat ter , cocoa are in terp lanted wi th coconutvar iet ies Yel low dwarf and Malavan ta l l . Inall three areas, the cocoa trees were spacedabout three meters apart. Thev were aboutse! 'en to ten vears o ld and bear ing.

Sungai Buloh Estate

Periodic observations about everythree months beginning Apr i l 1980 toDecember 198 1 were carr ied out in a markedtrapping gr id of 10 x 10 square p lot . Eachtrap-point was nine meters apart, and coversa total area of about 0.8r1 ha. During theseoccasions, animals were l ive-trapped forthree trap nights. A total of 200 traps wereutil ized of which 100 were placed at the baseof the trap-point (a cocoa tree) and the other100 above ground (tied to a tree branch ofthesame trap-point). Fresh coconut meat wasused as bait. Rats caught during eachtrapping round were identif ied to species,tall ied and removed. Nest counts for the plotwere carried out after each trapping round.The animal populations were estimatedbased on the removal techniques(Cnucsr-pv ,1977).

*Cocoa-coconut Branch, MARDI

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Kuala Bernam Estate

Sirn i lar p lot s izes and t rapping gr idsuere used. For cc lcc la p lanted l rnder var iet tN{ala lan ta l l coconut . the t rapping rnetho-dolo-er and nest count ing were s imi lar to thatc lescr ibed prer iousl r ' . But for c t tcoa undcr\ l t r i c t \ Yc l l o r r t l uA r t coconu t \ . t r i l pp in ! . u i t \a t r no re f r equen t i n t c r r a l s . e r e r r l l l 9davs. Ani rnals capturecl u ere car- tagged' , r . i th nur-nbered N' Ionel - rneta l No. I f inger l inctags. Simi lar recorc is r ' ,ere col lectcc l br , r tanimals r i .ere then re leased at the point t t fcap tu re . The ra t popu la t i ons \ \ e re es t ima tcdr - r s i ng t l r e mu l t i p i e recap tu re t echn ique basec lon the compu te r p rog ra rn $ r i t t en t r r KREes( l 9 7 l ) .

The co r re la t i on u r l r l r s i s he tnecn r r cs tnuntbers ancl the cst i rnate c l rat populut iorrs* ere analvzed usinc thc SPSS c() l l rputcrp rog ran r (N tp . HL , t - t - . J t , . r . ' x l r - s .S re rNeRENxER anc l B r , x r . 197 . i ) . O r l l \ r hcrc lat ionships for cocoa uncier duar fcoconutsu cre analvzed because nr( ) rc- d; i ta * e rc ar l i i l -l th le l ts conrparcc i to thc ot l i r : r i ' , ' , o i r rc i rs .

RI 'ST' I -TS

At Sunga i Bu loh Es ta t c . t hc ra t s caL lgh t\ \ 'ere r rost lv Rdt t t ts t ior r tur t i t ' t r .s (N. l r l ler ) .- l -her

bui l t the i r nests in fa l len c lead barks ofthe .-1 /bi:: ia shacle trees that got loclgecl in thecocoa canopics ( F igure /a/ . Dead harks thatfe l l on the grouncl \ \crc a ls( ) founcl to hesu i t ab le nes t i ng s i t es . The nes ts \ \ ' e re bu i l t h rstacking green ancl o ld dr ied lear es in to thesc-ba r ks .

S i rn i l a r l r a t Kua la Be rnam Es ta te . R .t iontunict ts \ \ 'c re caught most . For cocoaintercropped n i th duar f coconut var ietv thenest s i tes o l the rats uere l t tc i r ted u i th in thecoconut cro\ \ 'ns (F igure 1bi . Nests u 'ere bui l tin betu 'een the spaces at the i ix i ls of thecoconut frorrds or inf' lorescence and the treetrunks. The nest ing mater ia ls were o ld f rondsheaths and coconut leaf b lades wi th themidr ibs removed. Somet imes cocoa leaveswere a lso used, and these mater ia ls n 'ere

l ined and stacked in these spaces.

As for cocoa p lants in tcrcropped u i th ata l lcr c( )conut r ar ie t l . t l rc nests \ \ 'ereotrserrec l in the cocoa canopies (F igurc l t ) .Nests 'ur .ere bui l t h l s tack ing qreen arrd o lc lc l r ied cocol r leur es on top t l f cocoa branches.The leavcs \ \ 'ere arranged such that thebranches pror ided thc f ranteuork support .Nests uere a lso ot rsennecl i r r loose coconutf rLr i t hurrch sta lks uhich had c letacheci andgot lodge d in the cocoa canopies 1 F igure I d t .Ne-st ing rnater ia ls cornposed main l r o f coct laleaves stackcd in the boat-shapecl sp i r the.I -oosc coconut f rc inds that fe l l and remained()n the coc()a canopics a lso pror idedercel lcnt f ramcu ork \upport for nestl l L i l l L l t n g .

\ \ ' i th lhe except ion of nests bui l t incoc()nut cr ( ) \ \ ' l rs . the nest ing mater ia ls com-l rosed n i t ' rs t l r o f cr ' rcoa leaVes. \er" lv bui l tl tcsts can be d is t inguished f rorn o ld ones b 'nthe decrcc ot qreeness in the ncst ingr ra te r i a l s . Ncs ts u i t h n ros t l v b rown . d r i cdlund o ld cocoa leares inc l icate o ld nests thatLrsual lv h l i t l bec-n abrrndoned.

Dur i r rg most of the i rest - inspect ionrounds in a l l three areas. i t \ \ 'as noted that( )ne coconut or cocoa t rce $ ' i l l on lV house onenest . The inhabi tants of occupied nestsusua l l v i nc luded e i t he r a f ema le . a pa i r w i t h

) ( ) ungs o r r " i t hou t . ( ) r \ ( )mc t i n l c \ j u \ t \ ounp \( I - J r oungs ) . Dr ied cocoa beans u 'erel requenth observed in these nests.

The corre lat ion analvs is between nestnumbers and thc est i rnated rat populat ionsr . r i th in the t rapping gr ids of cocoa inter-cropped u'ith duarf coconut w'as significant( P<i) . 0 I ) . The interre lat ionsh ip w'as posi t ive( P e a r s o n c o r r r = 0 . 7 1 - 1 5 . 1 2 : 0 . , 5 1 0 5 , n :30. see Figure 2).

DISCUSSION

Knowledge of the nesting habits of theMalaysian wood rat the dominant rodentspecies in most cocoa plantings (FlaN andBosE. 1980; KaUaRUDIN et u l . , 1983),would be an invaluable asset when init iatingcontro l programs. The abi l i tv to re late the

82

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83

f r l

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100

Figure 2. Interrelationship of nest counts and the estimated rat population at Kuala Bernam Estate(cocoa under dwarf coconut) between April 1980 to December 1981.

1 1 030

rats' nesting sites to the types of cocoacropping systems practised for that particulararea would be advantageous. The obviousapproach then would be towards habitatmanipulation to reduce the attractiveness olthe cocoa eco-system for rats' inhabitation.Through good cultural and sanitary practicessuch as regular canopy shaping and pruningof the cocoa trees, suitable nesting sites couldbe reduced. The rats are denied of suitablenest framework and support for nestbuilding.

In addition, for monocropped cocoa(under Albizzia shade trees) periodicremoval of the dead tree-barks that gotlodged in the cocoa canopies and on theground needs to be undertaken. Perhaps ashade tree that does not easily debark shouldbe planted instead.

For those cocoa intercropped withdwarf or tall variety coconut palms, removalof loose coconut fronds that had got lodgedin the cocoa canopies would help restrict notonly the rats movements between canopies,but also reduce their potential of being a nestsite. Old fruit bunch stalks which provideexcellent nesting sites should also be perio-dically removed.

Good sanitary measures have beenneglected by most cocoa growers. Theconcept behind good sanitation is to lowerthe carrying capacity of the area for rathabitation. Such a practice would providethe first line of defence and fits into today'sapproach for integrated pest control.

Since there was a good correlationbetween nest numbers and the estimated rat

84

density, the former can be used as an index toestimate the rat's population for a particulararea. But as has been reported elsewhere(KavenuorN, 1982), it must be cautionedthat unless the true estimates of the animalnumbers have been derived, nest counts inthis study only explained 51 percent of rhevariabil ity of the estimated rat populations.

ACKNOWLEDGEMENTS

The author thanked Mr. Tan Hens

REFERENCES

CaucHl-Ey, G. (1977). Analysis of verte-brate populations. John Wiley andSons, New York, 234 pp.

HAN, K.J. and BosE, S. 0980). Somestudies on the mammalian pests incocoa planted under coconuts. Planter,Kuala Lumpur, 56, 273-283.

KanRnuolN, K.A., TURrzaN BRsanr andAso. Raue MauLuo fl983).Komposisi dan tabiat rodensia perosakkoko. Teknol. Pert. 1. 101- 107 .

KRuaRuorN, K. A. (1982). The ecology,pest status and control of the Malaysianwood rat, Rattus tiomanicus (Miller), ina cocoa-coconut plantation. Ph. D.Thesis, Michigan State University, 111pp.

Accepted for publication on ITth November, 1983

85

SUMMARY

The nest ing habi ts and interre lat ionships of nest numbers to est imated rat populat ions of theMalaysian wood rat, Rqttus tiomanicas (Miller), in three cocoa cropping sysrems were investigated. Formonocropped cocoa, the rats built their nests in the dead barks of A/blzlla shade trees. Nesting materialscomposed mainly of cocoa leaves. For cocoa planted under dwarfcoconut variety, the rats built their nestsin the coconut crowns, and nest ing mater ia ls were made up of o ld f rond sheaths and leaf b lades. The ratsbuilt their nests from cocoa leaves on branches in the cocoa canopies if cocoa were planted under tallcoconut variety. There was a good correlation between nest numbers and the estimated rat populations inthe study plot of cocoa under dwarf coconut palms.

Choon (Sungai Buloh Estate) and Mr. LohHang Pai (Kuala Bernam Estate) for accessto their plantations. Interest shown by theformer Director of Perennial Crops,MARDI and the Head of Branch on thestudy were appreciated. The author alsoacknowledged the assistance rendered bvRaub. Tur izan. Haj i . Bokhar i . tdr is . Zain i land members of the Crop Protection Unit,MARDI Hi l i r Perak.

Kness, C.J. (1972) Computer programs forthe analysis of demographic data fromsmall mammal populations. Universityof British Columbia, Mimeo. , 17 pp.

Meowey, Lono, (1969). The wild mammalsof Malayct and Singapore. OxfordUniversity Press, New York, 128 pp.

NrE, N.H., Hur-I , C.H., JENTINS, J.G.,STE,NBREN'NER, K. and BENT, D.H.( 1975). Statistical packoge for the socialsciences (Second edition). McGrawHill Book Company, New York. 675pp.