Little Ravens 'Corvus mellori' hunt, kill and eat individuals of two species of shorebird

2012·0.86 MB·English

NaturalistNotes
Little Ravens Corvus mellori hunt, kill and eat
individuals oftwo species ofshorebird
The Little Raven Corvus mellori is an omni- shorebird species as prey ofLittle Ravens that
vore that occasionally eats small birds. Most was capturedbyapparentlyco-operative hunt-
birds taken are thought to be eaten as carrion, ing.
though several records exist ofravens hunting WithoutknowingtheconditionoftheSharp-
and killing Budgerigars Melopsittacus undu- tailed Sandpiper before it was killed, we are
latus and a Spotted Turtle-Dove Streptopelia unable to conclude whether this species con-
chinensis (Higgins et al 2006). Both cases of stitutes a regularpart ofthe Little Raven’s diet.
bird depredation record Little Ravens attack- Thismayhavebeenanopportunistickill,given
ing from above and stabbing prey to death theSharp-tailed Sandpiperwas alone, whichis
with theirbeaks. Here, we report a pairofLit- somewhatunusual.
tle Ravens hunting, killing and eating a lone
Red-cappedPloveradults,eggsandyoung
CShhaerept-thaaimleWdetSlaannddpsi,penrearCaMleidlrbiosuranceu,miVniicttaoriaat On 11 November 2010, KE was conducting
(37« 53’ 56”S, 144° 47’ 33”E; 420 ha; see Antos field work on Red-capped Plovers (Ekanayake
etal 2007 foradescription). Wealso reportan 2011)andobservedapairofLittleRavensmov-
ing along a raised embankment. Red-capped
event which strongly implies they hunted and
ate an adult Red-capped Plover Charadrius ru- Plovers nest on these embankments and adja-
ficapillus, and observations ofhunting and eat- cent edges ofthe ponds in the study site (By-
water 2009). Both ravens were carrying prey
ingeggsandchicks.
in their beaks. When approached, one raven
Sharp-tailedSandpiper was seen consuming a bird, the other, an egg.
On 17 March 2010 we were conducting field Startled bymy presence, the ravens tookoffto
workaspartofabreedingstudyofRed-capped a nearbypower pole, dropping the preyto the
Plovers (Bywater 2009; Ekanayake 2011) when ground. Upon closer inspection it was found
we noticed apairofLittle Ravensswoop down thatthe preywas a Red-capped Ploveregg and
fromaperchonpowerlines,toasmallchannel an adult Red-capped Plover, ofwhich onlythe
that is used extensivelybyforagingshorebirds. right wing, part ofthe belly and the two legs
We witnessed a single Sharp-tailed Sandpiper remained. An ABBBS metal band and a flag
jumping up towards one ofthe ravens several withuniquetwoletterengravingwerefoundon
times,beforetheravenwheeledaroundandde- theleftleg; thebirdprovedto be a femaleRed-
scended at the location. The location featured cappedPloverthatwascapturedonhernestby
raised embankments on two sides ofthe chan- theinvestigatorson 12 March2010.
nel, uponwhich the ravens perched, effectively This predation event leads us to believe that
cornering the sandpiper. We momentarily lost Little Ravens either adopt aco-operativehunt-
sight ofboth raven and sandpiper, but within ingstrategy, or inthiscase, astrategyinvolving
halfa minute had driven to a point where we prey ambush, where theydetect an incubating
observed one raven consuming the recently Red-capped Plover and successfully kill it by
killed sandpiper. When our vehicle disturbed approaching from behind (many Red-capped
the ravens, they flew slowly along a roadway, Plover nests at the studysite are tucked under
carryingthesandpiper,andlandingoccasional- cover).TheconditionofthefemaleRed-capped
lyto eat moreparts ofit. Thisis the first record Ploverbeforeitsdeathwasunknown;however,
we are aware ofwhich documents a migratory it was likelyto havebeen in good condition as
22 TheVictorianNaturalist
NaturalistNotes
it was presumed to be an incubating/breeding nearbypowerlineswheretheywereconsumed.
bird (since the other raven was consuming a Thus, Little Ravens prey upon alllifephases of
Red-capped Plover egg) and its condition and Red-cappedPlovers.
thepresence oftheeggsstronglysuggest itwas Conclusion
noteatenascarrion.Nevertheless,thisprovides
These observations support other records indi-
evidence of Little Ravens’ ability to hunt, kill
andeat not onlyadultmigratorybutalsoadult catingthatLittleRavensareskilledpredatorsand
have theabilityto huntandkill smallbird spe-
residentshorebirds.
A pilot study using nest cameras has shown cies,includingtheireggsandyoung(Higginset
thatravens are themostcommon causeofnest al. 1996; Santisteban etal 2002). The studysite
failure amongRed-capped Plovers atthestudy features abundant ravens, present year round,
andtheyareconsidered avoraciouspredatorof
site (see Fig. 1 for a nest camera image). They
Red-capped Plovers (Ekanayake 2011 unpubL).
have also been seen actively hunting and eat-
ing young Red-capped Plover chicks. On 17 Giventhattheyaregenerallyregardedassuper-
tSleeptReamvbeenrs 2a0t0ta9c,kiwneg aobbsrerovoeddoaf pRaeidr-coafppLietd- ambauyndwaarnrtan(tBamrraentatgeetmaeln.t20i0n3f)u,tutrhee.ir activities
Plovers; locating the hidden chicks bywalking Acknowledgements
around theagitated parents, searchingin cover Ethics approval for this project was given by AWC
and in places atypical ofchick refuges, seizing SAl4a4d/e20F0o8u.ndTahtiisown,orMkAwasInsgurpapmorTtreudstbyanthdetHheerAmuosn-
them in their beaks and flying with them to tralianBirdandBatBandingScheme.Wealsothank
Fig. 1. A nest-camera image ofa Little Raventaking aRed-capped Plover eggatCheetham Wet-
lands.
Vol 129 (1)2012 23
NaturalistNotes
Bernie Mccarrick and John Argote from Parks Vic- Australian,NewZealandandAntarcticBirds.Vol.7A:Boat-
toria. billstoLarks.(OxfordUniversityPress:Melbourne)
SantistebanL,SievingKEandAveryML(2002)Useofsenso-
References rycuesbyfishcrowsCorvusossifraguspreyingonartificial
Antos MJ, Ehmke GC, Tzaros CL and Weston MA (2007) birdnests.JournalofAvianBiology33,245-252.
Unauthorised human use of an urban coastal wetland
sanctuary:Currentandfuture patterns.Landscape Urban AdamPCardilini,KasunBEkanayake
BarPrleatntniG,ngSSiOl,co1c7k3s-A1,83B.arryS,CunninghamRandPoulterR andMichaelAWeston
(2003) TheNewAtlasofAustralianBirds.(BirdsAustralia: DeakinCentreforIntegrativeEcology
Melbourne) SchoolofLifeandEnvironmentalSciences
BywaterJA(2009)Parentalcareandbreedingecologyofred- DeakinUniversity
capped plovers {Charadrius ruficapillus). (Unpublished 221 BurwoodHighway
HonsThesis,DeakinUniversity,Burwood) Burwood,Victoria3125
Ekanayake K (2011) Does sexually dimorphic ornamenta-
tion in birdsattractpredators aswellas mates? (Unpub-
lishedHonsThesis,DeakinUniversity,Burwood)
HigginsPJ,PeterJMandCowlingSJ(2006)TheHandbookof
A
‘naming tree’ story
Introduction werewatered occasionally over theirfirstthree
In2002,twoeucalyptseedlingswereplantedin years (in drought conditions). By 2011, they
DarebinParklands,Alphington,aspartofacer- hadbecomesubstantialself-sustainingsaplings
emonial naming dayfor six-month old twins. (height 10.0mand7.0mwithadbhof170mm
Almost nineyears later, the seedlings have be- and 110mm, Fig. 2).
cometallsaplingsofferingevolvinghabitatand The privateobjectives and incorporated pub-
amenity forwildlife and the public overfuture licgoodoutcomeswereto:
decades and beyond. Reflections on this sim- •provide a focal point for the family, and spe-
ple private activity are explored as a potential cifically the children, to watch and reflect
meanstoenhancepublicgoodconservation. uponthegrowingeucalyptsandthechang-
ingfaunaluseofthe treesby insects, birds
Description
On Boxing Day 2002, seedlings ofa Red Iron andmammalsovertheirlifetime;
BarkEucalyptus tricarpa and aRiver Red Gum • watch and observe other peoples enjoyment
m ofthesiteovertime;
E. camaldulensis(about0.6 high)wereplant-
ed in Darebin Parklands as part ofa naming • activelynurture nature in a public space and
provide a smallcontribution to the greater
day ceremonyforsixmontholdtwins (Fig. 1). conservationamenityofthesiteandtopro-
Thesespecieswerepartoftheoriginalrevegeta-
tionofDarebin Parklands byCam Beardsellin videdecadesofhabitatavailabilityforwild-
lifespecies,bothresidentsandvisitors.
theearly 1980s. Thespeciesarebothlong-lived
and flower at different seasons, with the Red The site is periodically visited and, to date,
is achieving the initial private aims. The trees
Ironbarkprovidingimportantwinterflowering
have anonymously melded into the overall
forarangeoffauna.Theseedlingswereoflocal
parklandsandwillflower inthenextfewyears.
provenance(obtainedfromLaTrobeUniversity
They‘belong’totwopeoplebutsimultaneously
WildlifeReserve nursery) and plantedwiththe
toeveryone-aprivatemeaningwithatangible
permissionandplacementadviceofPeterWilt-
socialandenvironmentaloutcome.
shire(RangerofDarebin Parklands). Theseed-
lingswerestaked but otherwise unmarkedand
24 TheVictorianNaturalist