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POSSIBLEEFFECTS OF (AND/OR ) PREDATION ON GROUND NESTING IN WESTERNAUSTRALIA

BY ALLAN BI-IRBIDGEAND PHIL FLTLLER RESEARCHDIVISION September1990

SUMMARY

In Western 65 (excluding seabirds) nest on or in the ground. Of these,the Malleefowl and BushThick-knee (Stone-curlew) have declined signifi- cantly, at leastin part becauseof fox predation, although more researchis needed. The effectof fox predation on 38 speciesis unknown, butsignificant local effectsare Iikely and three species(Ground Parrot, Nullarbor Quail-thrush and Australian ) are believed to be at high risk and require further research.There has probably beenno significant effectofpredation on the remaining 25 species.Those most at risk appear to be the speciesspending the highest proportion of their time on the ground, but other (unknown) factors may also be involved.

INTRODUCTION

The tox (Vulpesoulpes) and f eralcat(Felis catus) arewidespread in WesternAustralia (Strahan1983; King and Smith 1985).Both specieshave been regarded as seriow predators of native fauna (e.g.Christensen 1980; B.J. Coman in Strahan 19g3;E. Jonesin Strahan1983). Despite this, there hasbeen very little study of the effectsof either predator on individual speciesofnative .Onenotable local exception is a study which has shown that limit numbers of rock-wallabies (petrogale lateralis)in theY,'lestem Australian wheatbelt (Kinnearet al -'t988).However, effects of foxes or on native birds have not been sfudied in Western Australia.

The primary aim of our study, therefore,was to provide a preliminary assessment of the possiblemagnitude of predation by foxesand/or cats on thosebird species most at risk, the ground nesting species.A further aim was to help acquaint land managercwith this knowledge and to appeal for any further information.

GROUND NESTING BIRDS

Predation by foxes or cats on ground-nesthg birds is likely to occur through predation on eggs,nestlings, incubating adults, brooding adults or, in some cases such as the Malleefowl, on young birds which are as yet unable to fly. Table 1 lists speciesaccording to the level of predation which is believed to occur"It does not include most seabirds,the majority of which nest on off-shore islands and are thereforemostly protectedfrom foxesand cats.Thelist doesinclude severalspecies which nest in creekbanksand similar situations.Allocation ofspeciesto categories in the fist is subjectivedue to lackofdata. Most speciesare therefore classified as,IJ', i.e.effects unknown, butbelieved to bevulnerable.Somespecies are abundant even where foxesare common, or elsenest only infrequently in placesvulnerable to fox 'I predation, and are classiJied (insignificant risk). A few specieshave declined significantly in numbersand/or rangeand arehighly likely to be predatedbyfoxes. These are classified as ?I' (high risk). AII classificationsare best considered as speculative.

Two speciesare believed to have suffered significantly from predation, probably primarily from foxes.Fox predation is a major causeof juvenile mortality in the Malleefowl in New SouthWales and SouthAustralia (Priddel 1989;p. Copley, pers. comm.) and presumably throughout the geographicrange of the bird. The Bwh Thick-knee (Stone-curlew)has disappearedfrom many areas and decreasedin numbers in many others.This declinehas oftenbeen attributed to habitat alteration (Blakerset al. 1984).However, its disappearancein at least some areashas been correlatedwith the arrival o{ the fox (Storr and Iohnstone1989) and the speciesis still common on some off-shore islands in easternand Western Australia from which foxesare absent,even though there are developmentalpressures on some islands (A.A. Burbidge pers.comm.; J.E. Kinnear pers.comm.; A.H. Burbidge pers. obs.).They are also still relatively common in hard spinifex areasof the pilbara, where foxes are relatively uncommon (A.N. Start pers. comm.). More researchis neededto determinethe effectsand importanceoffox predation on thesespecies in Western Australia.

For many other species,the sihration is lessclear. However, severalseem to be at higherriskthan others,and so havehigh priority with respectto future research.In Western Australia, the Ground Parrot has declined in numbers and range to a greater extent than in easternAustralia (Burbidgeet a\.1989).In parts of Western Australia, this is apparently due largely to inappropriate fire regimesin the past. However, the fox hasalmost certainly played a role in the observeddecline. Fufure planned fox baiting in FitzgeraldRiver National Park,in coniunctionwith monitor- ing of Ground Parrots, will shed more light on this question. Interestingly, the Ground Parrot has declined markedly on the mainland, but apparently not in Tasmaniawhich is now its stronghold (Meredith 1984),and where the fox is absent.

The Nullarbor Quail-thrush has also undergone a widespread decline,which has usually beenattributed to habitat degradation.However, the fox is common on the Nullarbor and the Quail-thrush is absent from some apparently suitable areas "1984), (Blakers et al. suggestingthat predation may be an important factor in the decline.

The Bustard has declined more in southern than in northem and desert regions of Australia, where the fox is lesscommon.It is likely that grazing by rabbits,landuse practicesand predation by foxesall act to limit numbers of (Grice et al. 1986)but more researchis needed.

Even large birds may be susceptible:brood reduction is often marked in the Emu, and this may be causedby predation of youngby foxes,although this is unlikely to be a maior limiting factor tbr this species.

The list in Table 1 should be viewed asbeing speculativerather than authoritative. Severalother species,including chats,fairy-wrens and emu-wrens,nest near the groundandhence aresusceptibletofoxand catpredation, although this is notlikely to be significant.

DISCUSSION

Little is known of the effectsof foxesor catson native bird populations in Westem Australia. Mostcurrent work onferal predatorsison foxes,butit is known that both feral and domestic cats (E.Jones in Strahan1983; Paton 1990a,1990b)exert some predation pressureon native birds.

An additional difficulty encounteredin making assessmentssuch as thatattempted here is that foxes and cats are adaptableand opporfunistic predators, capableof switching prey items quickly (E.Jones in Strahan1983; J.E. Kinnear pers. comm.). One consequenceof this is that prey speciesof the fox (and presumably also of the cat) vary widely betweenlocalities and betweenseasons, with the result that birds can be important prey items in someseasons at somelocalities but not others (e.g. Mclntosh 1963;Ryan and Croft'1974). TABLE 1: Possible Effects of Fox (and,/or cat) predation on Western Australian Ground-Nesting Birds (excluding Seabirds).

Key: S = predation by foxesbelieved to have been at least partly responsiblefor significant decline in range or numbers H = unknown, but risk thought to be high IJ = unknown, but significant effectslikely in at least some sites I = effect of predation by foxesbelieved to be insignificant

Commonname Scientificname Elfect

STRUTHIONI FORI,4ES : ENTU Emu Dro mai u s novaeholl andiae

PELEoANIFoRMES:PELIcAN AustralianPelican PeI ecan u s co nspicill atu s

ANSERIFORMES:DUCKS AND GEESE CapeBarren Goose Cereopsis novaeholl andi ae I AustralianShelduck Tadornatadornoides * PacilicBlack Duck Anassuperciliosa GreyTeal Anasgibberitrons ChestnutTeal Anascastanea AustralianShoveler Anas rhynchotis ManedDuck Chenonettajubata *

GALLIFORN,| ES: MALLEEFOWL, QUAILS Orange-footedScrubfowl Megapodiusreinwardt l\4alleefowl Leipoaocellata - StubbleQuail Cotum i x novaeze I and iae U BrownQuail Coturnixaustralis U KingQuail Coturnixchinensis

GRUIFORMES:BUTTON-QUAILS, BUSTARDS Red-backedButton-quail Turnixmaculosa PainledButton-quail Turnixvaia U Chestnut-backsdButton-quail Turnixcastanota LittleButton-quail Turnixvelox I Red-chestedButlon-quail Turnixpyrrhothorax I AustralianBustard Ardeotisaustralis n

CHARADRIIFORMES:WADERS AND TERNS BushThick-knee (Stone-Curlew) Burhinusmagnirostris S BeachThick-knee (Stone-Curlew) Burhinusneglectus U PaintedSnipe RostratuIa benghal ens is PiedOystercatcher Hae matopu s longiro;tri s SootyOystercatcher Hae m atop us t ulig i nosu s MaskedLapwing Vanellusmiles I BandedLapwing Vanellustricolor Red-kneedDotterel Erythrogonyscinctus I Black-frontedPlover Charadriusmelanops HoodedPlover Ch arad ri us rubricoII is " almostexclusively tree hollow nesters, but downy young susceotibleto oredationen routeto water.

4 (Table1 cont.) Commonname Scientificname Effect Red-cappedPlover Charadriusrulicapil Ius lnlandDotterel Peltohyasaustralis U Black-wingedStilt Himantopushimantopus BandedStilt Cl adothynchus Ieucocephalus Red-neckedAvocet Recuruirostra novae h oll and i ae U AustralianPratincole Stiltiaisabella FairyTern Stemanereis U

COLUMBIFoRMES:PIGEONS FIockBronzewing Phapshistrionica I WhitequilledBock-Pigeon Petroph ass a albipe n n i s I SpinitexPigeon Petrophassaplumilera U

PSITTACIFORIVIES:PARROTS GroundPanot Pezoporuswallicus n NightParrot Geopsittacusoccidental is RockParrot Neophemapetrcphila I

CAPRIMULGIFORMES:NIGHTJARS spottedNightjar Captimulgusguttatus U

CORACIIFORi/lES:KINGFISHERS Red-backedKingfisher Halcyonpyrrhopygia RainbowBee-eater Meropsornatus

PASSERIFORMES:SONGBIRDS Pittas RainbowPitta Pitta iris

Larks SingingBushlark Miratrajavanica

Swallows White-backedSwallow Che ram oeca Ieu coste rnu m

Pipits Richard'sPipit Anthus novaeseeIand iae

Scrub-robins SouthernScrub-robin Drymodesbrunneopygia

Quail{hrushes ChestnutQuail-thrush Cinclosomaca€tanotum cinnamonQuail-thrush Cincl$oma cinnamomeum NullarborQuail-thrush Cinclosomaalisteri H

Songlarks RulousSonglark Ci nclorh amph us mathewsi U BrownSonglark Ci nclorh amph us crural i s U

scrubwrens& allies ShyHylacola Sericorniscautus U Redthroat Sericornisbrunneus U Sericornis f uli g i nosus I

Pardalotes SpottedPardalote Pardalotuspunctatus Yellow-rumpedPardalote Pardal otus xanthopygu s

5 While the extent of predation effectson birds is thereforeunknown, it can be seen from Table 2 that up to about 10%of the breeding birds of Western Australia may be affectedto someextent by predation by introduced predators.Predationby foxes is believed to be implicated in the declineof at leasttwo speciesof birds inWestern Australia. Predation is very likely implicated in the decline of a number of other species,but data are lacking.

As pointed out above,almost allseabirdsnest on off-shoreislands, where foxesand catsdo not occur.However, one exampleof presumedfox predation on seabirdsis the loss of the breeding colony of Wedg+tailed Shearwaters(Pffinus pacit'icus)on WedgeIsland (north of Lancelin)following developmentof a tombolo joining of the island to the mairrland around 1960(Ford 1965;P.I. Fuller pers. obs.).

Table 2: Summary of known and possible effects of fox and/or cat predation on ground-nesting birds in Western Australia.

* * Category No.of species % of total 7oof breeders*

Significant

Total 13 18

* includingseabirds and speciesnot nestingin WesternAustralia (ca.492) * * 356 breedingspecies, excluding Procellariitormes, tropicbirds, trigatebirdsand boobies, but includingterns

CALM land managersare encouragedto document any perceivedchanges in the abundanceofnative birds (or other animals)following any fox baiting programs on reservesor elsewhere.Please communicate any observationsto either Allan Bur- bidge or Phil Fuller at: WA Wildlife ResearchCentre PO Box 51 WANNEROO 6065 Tel. (09)405 5100 REFERENCES

Blakers,M., Davies, S.J.J.F.and Reilly, P.N' (1984)The Atlas of Australian Birds' Melbourne University Press,Melbourne.

Burbidge, A.H., Watkirs, D. and McNee,S. (1989)Project 118: Conservation of the Giound Parrot in Western Australia. Unpublished report to World Wildlife Fund (Australia).

Christensen,P.E.S. (1980) A sad day for native fauna. ForestFocus 23: 3-12'

Ford, I. (1955)The aviJaunaof the islandsbetween Dongara and Lancelin,Western Australia. Emu 54: 129-1'M.

Grice, D., Caughley,G. and Short,J. (1985)Density and distribution of the Australiin Bustard Ardeotisaustralis.Biological Conservation 35: ?59-267 '

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Kinnear, J.E.,Onus, M.L. and Bromilow, R.N. (1988)Fox control and rock-wallaby population dynamics. Australian Wildlife Research15: 435-450'

Mclntosh, D.L. (1953)Food of the fox in the Canberradistrict. CSIROWildlife Research8: 1-20.

Meredith, C.W. (1984)RAOU conservationstatement no. 1. The Ground Parrot Pezowruswallicus Kerr. RAOU Report No. 10.

paton, D. (1990a)Domestic cats and wildlife - results from initial questionnaire. South Australian Ornithological AssociationNewsletter No. 133:1-4'

Paton,D. (1990b)Domestic cats and wildlife. Resultsfrom initial questionnaire'Bird ObserverNo. 696: 34-35.

priddel, D. (1989)Conservation ofrare fauna:theRegentParot and theMalleefowl. Ch. 15 (pp. 243-249)fu J.C'Noble and R.A. Bradstock(eds) Mediterranean Landscipes in Australia: Mallee Ecosystemsand their Management'CSIRO, Melbourne.

(1974) food of the fox, Vulpesaulpes Ryan,' G.E.and Croft, J.D. Observationson the (L.), in Kinchega National Park, Menindee,N.S'W. Australian Wildlife Re- search1: 89-94.

Storr, G.M. and Iohnstone,R'8. (1988)Birds of the SwanCoastal Plain and adjacent seasand islands.Records of the WesternAustralian Museum Suppl' No' 28'

Strahan,,R. (ed). (1983)The Complete Book of Australian Mammals' Angus and Robertson,SydneY' 0952-1190-5oO

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