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Research Reports Birds ofSeal Rocks in northern Bass Strait over40years (1965-2005) RobertM. Warneke1 and PeterDann2 'BlackwoodLodge,1511MtHicksRoad,Wynyard,Tasmania7325. ResearchDepartment,PhillipIslandNatureParks,P.O.Box97,Cowes,PhillipIsland,Victoria3922 E-mail:[email protected] Abstract Long-term datasets offauna are rare for uninhabited islands in south-eastern Australia. Herewe report on 40years ofobservations from 1965 to 2005 on thebirds ofSeal Rocks in northern Bass Strait. Seventy-five nativeandsixexoticspe—ciesincluding21 nativepasserineswereobservedatSealRocksornearby. Sixspecies were recordedbreeding CrestedTern Thalasseusbergii. SilverGull Chroicocephalus novaehollandiae, Sooty OystercatcherHaematopusfuliginosus.WelcomeSwallowHirundoneoxena,CommonStarlingSturnusvulgaris and,forthefirsttimeinVictoria,KelpGullLarusdominicanus. Themainchangestobreedingbirdsoverthe 40yearshavebeenthemovementandexpansionofthebreedingcoloniesofCrestedTernsandSilverGullsto adjacent parts ofnearby Phillip Island, and the arrival and expansion ofthebreeding Kelp Gull population. Kelp Gullshave increased substantiallyatSeal Rocks sincetheirarrivalin 1968. Thefirstreportedbreeding forVictoriaoccurredtherein 1971.TheexpansionofKelpGullsmayhavebeenassociatedwiththeexpansion ofAustralianFurSealArctocephaluspusillusdoriferusnumberswhich,ononehand,hasreducedthenumber ofsuitablebreedingsitesbut, on theotherhand,hasincreased theamountoffoodavailableintheformsof vomitedfoodremainsandplacentae.ThevarietyoflandbirdsrecordedonSealRockswassurprisinglyhigh, given theexposednatureandrelativesterilityoftheterrain;however, thestraitbetweenSealRockandPhil- lip Islandisnarrowandallthespecies recordedtherearecommonintheregion andmostarewide-ranging seasonallyorundertakesignificantnorth-southmigrations. Recordswererelativelyfewafter1997due,inpart, tothereducedamountofvegetationontheisletsandgreatlyreducedlengthsofresearchstays. (TheVictorian Naturalist130(1)2013,4-21). Keywords:SealRocks, PhillipIsland,birds,long-termsurvey Introduction SealRocks(38°32’S, 145°06’E),aStateFaunal Field studies were initiated in 1965 by the — Reserve, comprisestwosmallislets SealRock Fisheries and Wildlife Department (now the and Black Rock—which lie about 1.5 km off Department of Sustainability and Environ- the south-west pointofPhillip Island, Victoria ment) andsupported until 1979. Afieldstation (Fig. 1). SealRock,thelargerislet,includestwo was built on the southern plateau ofSeal Rock detachedrockstothenorth-westandanexten- in the summer of 1965-1966 (Warneke 1966) sive area oflow-lying reefto the east, which is andsubsequentlyother structureswere erected cut offathigh tide (Fig. 2). Thetotal land area tofacilitateaspectsoftheprojectincludingafly- isabout2.8ha. ing-foxconnectingthetwoislets(1967),asmall AlthoughSealRockshashadalonghistoryof observation hide on each ofthe Seal Rockpla- visitsbyEuropeansdatingfrom 1801 (Warneke teaux(1967) anda 15msteelobservationtower 1982,2003),veryfewdetailedaccounts survive adjacent to the station (1969). Most ofthis in- and none provide any useful information on frastructure was demolished by 1979 when a the vegetation or bird life. This paper reports second field stationwas builtoutofrock atthe on incidental sightings and observations on baseofthenorthernendofSouthPlateau. birds ashore andatseaaround the islets, accu- A small research team visited Seal Rocks at mulated during a program ofresearch on the approximately monthly intervals from 1966 resident colony of Australian fur seals Arcto- until 1972, but thereaftervisitswere limitedto cephaluspusillus doriferus by Robert Warneke November and December each year to moni- , (1965-1991) and continuing studies there on tor events during the breeding season and to fur seals and birds by Roger Kirkwood (RK) count pups. Pups were routinely marked each and Peter Dann (1998-2005). Datasets ofsuch January until 1977. From 1979 to 1991 RMW duration are rare, particularly for uninhabited continued the November-December monitor- islandsinsouth-eastern Australia. 4 TheVictorianNaturalist Research Reports 144*E 145*E 146*E Fig.1. LocationsofSealRocksandPhillipIslandinBassStrait,south-easternAustralia ing and counting on a private basis until, by The data accumulated under these circum- 1991, very fewmarkedanimals remained alive stances,especiallyduringthemostintenseperi- (Warneke 2003). More recently, Seal Rockhas odofsealresearchfrom 1966to 1972,providea beenvisitedon40occasionsbetween February fairlyclearpictureofbirddiversityontheislets, 1997andApril2005byPDandRK.Mostvisits includingtheoccurrence ofseasonal migrants. wereofseveralhours’durationbutseveraltrips Most observations were made with the aid of lasted3-4dayswhilesatellitetransmitterswere Zeiss 8 x 30 binoculars, and frequentlyan 800 deployedonfurseals (Kirkwoodetal. 2005). mm telescope was used for closerviewing ofa Opportunities for observation were con- particular bird or activity. The effective visual strained by the demands of the seal study, rangewasusuallyabout 1 kmforlargeseabirds and although new’ or rarely seen species and or congregations, and as far as 3 km in clear significant activities were always duly noted, weather using the telescope. Observational ef- observations on resident species were not sys- fort differedbetween theperiod ofintense seal tematically recorded. Visits to many parts of research (1966-1972) andthelateryears (1997- Seal Rock were consciously limited, to avoid 2005).Thesearereferredtohereafterasthefirst disturbing the seals, and extra care was taken and second survey periods respectively. Bird when birds were nesting; visits to check the observations in the later years were confined contents ofparticular nests were cautious and to the islets and waters immediately adjacent, brief. Landings on Black Rock were difficult using 10 x 20 binoculars; consequently, many and risky until the flying foxwas in place, but fewerpelagic seabirdswererecorded. eventhenthatisletwasvisitedonlyforspecific Records of birds summarised here consist taskssuchastaggingsealpups. ofnotes in RMW’s field journals, to which all Vol 130 (1) 2013 5 Research Reports team members1 contributed sightings; brief caniceventsandconsistofdepositsoftuffover- entries in surviving personal diaries kept by lainbylavaflows.Stormwaveshaveerodedthe Fred Baum (1965-1968, 1970-1971) and Kevin softertuffandthishas ledto undercutting and Chipperfield (1968), whichincludevisitswhen rockfallsfromabove.Manyclifffacesaresheer RMW was not present; and Phillip Island Na- with narrowledges, andshallowcaves occurat ture Park research groups records of40 visits thesouth endofSouth Plateauandonallsides between 1997 to 2005. A negative linear bino- ofBlackRockscentralplateau. mialgeneralisedmodelwasusedforlookingat Landplants surviveonlywherethesealshave the seasonal pattern ofKelp Gull numbers us- no oronlylimited access, i.e. on clifffaces and ing Rsoftware (version 2.15.1; R Development some parts ofthe plateaux tops. Gravel from CoreTeam2012). weatheringofthevolcanic rocktends to accu- PhysicalandbiologicalfeaturesofSealRocks mulate on ledges and in fissures on clifffaces, and supports clumps and mats of Rounded The continuing effects oftides and storms on Leaf Noon Flower Disphyma australe. Along thegeologyofthe isletshave resulted in avar- the margins of abrupt cliff tops, where rest- iedtopographyofplateautops,cliffswithledg- esandundercuts,caves,gullies,boulder-strewn ing seals are less inclined to lie, this plant has upperslopes,cobblestone-pebbleshingle,worn a precarious hold and generally forms a nar- rowridge-like mat. SeedlingsofRubySaltbush wave-washed shore platforms with some deep Enchylaenatomentosawereoccasionallyfound, tide pools, and many ephemeral tide pools apparentlyimportedviabirdfaecesorpellets.If flushed onlybythehighesttides orstorm seas. theygerminatedinprotectedplacesonthecliffs Both islets are basically low platforms offine- they flourished for several years. Other colo- grained black basalt surrounding areas ofpla- m nistswereBowerSpinachTetragoniaimplexico- teauxofvaryingheighttoabout12 abovesea ma Cape Weed Cryptostemma calendula Sow level. These plateaux are remnants oflatervol- , , 6 TheVictorianNaturalist Research Reports Thistle Sonchus sp., a nightshade Solarium sp. AustralianShelduckTadorna tadornoides and Boxthorn Lyciumferrosissimum, but, with A line ofseven passed by to the north on 20 the exception ofBower Spinach and Southern December 1974flyingtowardsthewest. Sea-heath Frankeniapauciflora, none survived PacificBlackDuckAnassuperciliosa forlong. Small mats ofBeaded Glasswort Sali- A pair on 19 October 1970 flying slightly east cornia quinqueflora were found on BlackRock plateau in 1968 and 1971. A profusion ofma- ofsouth,buttheyturnedwestbeforebeinglost toview. rine plants and invertebrates occurred at the edges ofthe shore platforms and on East Reef RockDoveColumbalivia in theintertidal zone, includingseaweeds,kelp Seven sightings of lone birds during the first Macrocystis sp., cunjevoi Pyura sp., barnacles, survey period, in January and between May limpets, chitons, mussels (mainly Xenostrobus andAugust,andoneofagroup ofthreeinNo- sp.) andthegastropodsSubninellasp. andNer- vember. Mostwereseen flyingover orpastthe ita sp. were very common. Dense beds ofkelp isletsandgenerallyinanortherlydirection. On also occurredintheshallowbayformedbythe twooccasions,lonebirdslanded. twoisletsontheeasternside. CommonBronzewingPhapschalcoptera The insect fauna appeared to be diverse and mostformswere seen onlyduringthewarmer Onerecordonly,ofabirdseentopitchintothe months. It included field crickets Teleogryllus noon flower sward at the north end ofSouth commodus atleast six different kinds ofwasps Plateau on 24 April 1968. It appeared to be (especially,the orange ichneumon Netelia sp.), moulting, havingonlyoneremainingloosetail ablack ant and a smallblacknative bee;blow- feather. flies (Calliphorasp.) andasmallblackflycom- White-throated Needletail Hinindapus caudacu- mon in humidweatherandattractedto sweaty tus skin; dragonflies and damselflies; moths (most Onesightingofalonebirdthatpassedlowover notablyAgrostis sp.) and butterflies (including Seal Rock from the north-east at 17.30 hr on Vanessa kershawi), and mosquitoes, noticeable 17 January 1969 shortly after a north-westerly onlywhen a sheltered depression in the lee of change.Thisspecieshasbeen sightedovertidal thesouthendofNorth Plateauwassporadical- flatsonWestern Port(DaviesandReid 1975b). lyfilledbyseasprayandrainshowers,inwhich White-facedStorm-PetrelPelagodromamarina larvaewereobserved. Onerecordofabirdthatflewintothefieldsta- Speciesnotes tionthroughtheopendooron 18October1967 Nomenclature and systematic order follows at20.00hr. Christidis and Boles(2008). WanderingAlbatrossDiomedeaexulans StubbleQuailCoturnixpectoralis Twenty-two sightings offshore during the first Eightrecords oflone birds sightedon orabout survey period, between mid-June to mid-No- South Plateau, among the mats ofnoon flower vember,andtwoadditionalrecordsinmid-Jan- or in the cover ofrocks, in Novemberof1965, uary. Most sightingswere oflone birds gliding 1967and 1969,December 1971,andinOctober in rough windy weather, well offshore within and December 1975.Thedesiccatedremainsof a broad arc from the south-east to the north- a bird were found on South Plateau on 16 No- west,andpredominantlyduringsouth-westerly vember 1967. Specimen RW#465, collected 25 blows. Sixsightingswereoflonebirdsflying in November 1969 (MuseumVictoria). calmconditions. BlackSwanCygnusatratus Black-browedAlbatross7halassarchemelanophris Fourrecordsofbirds intransit;eightwereseen The most commonly observed albatross, from headingwest on 15 December 1969,one head- April to mid-December, but the majority of ing south on 19 December 1970, 11 heading sightings (247 of262) were from June to Au- west on 23 February 1972, and five heading gust; frequently in association with Shy Alba- north on 18November 1975. tross Thalassarche cauta. Peak numbers were Vol 130 (1)2013 7 Research Reports recorded in the latter parts of May or June, On three occasions a lone Giant-Petrel was usually on days of very rough weather. The seen ashore on the Main Beach breeding area, greatest concentration was noted on 23 June resting or walking among the fur seals with 1971 during a hard south-westerly gale, when wings partly opened. Juvenile seals and even over 200 were in view within an arc from the adultmalesretreated,whereascowswithyoung south-east to the south-west. This species was pupsrespondedwithopen-mouthedthreats. observed only once in the second survey pe- NorthernGiant-PetrelMacronecteshalli riodwhentenbirdswereseenon25May1999. Onlyonecertainrecordofabirdrestingonthe Despite frequent sightings close to shore early wateroffEastReefon 5 February 1979 (RMW, in the first survey period, feeding was rarely FTB). observed. On two occasions three to six birds fought over flotsam, identified in one instance SouthernFulmarFulmarusglacialoides asalargecuttlefish (probablySepia apama);on AlonebirdwassightedbyKJCflyinglowover another, two birds were observed harassing a NorthBeachatmiddayon22August 1968. seal thrashing a moderately large prey item at CapePetrelDaptioncapense thesurface, and on athird occasion several al- Eight sightings oflone birdsbetween June and batross paddled up to an Australasian Gannet September, ofapairon22August 1968,andof Morussenatorwhenitsurfacedwithafishand alonebirdinmid-December. Usuallyseen fly- attemptedtosnatchit. inglowoverthewater andifalighting onlyfor ShyAlbatross Thalassarchecauta briefperiods. On two occasions a Cape Petrel Active offshore in small numbers from late hoveredaboutinthevicinityofarestingGiant- April to mid-December (28 records), butwith Petrel, but no interaction occurred. Specimen no obvious peakor influxas in the case ofthe RW#216 collected 22 August 1968 (Museum precedingspecies. Possiblefeedingactivitywas Victoria). observed on 15 June 1969 when several birds FairyPrionPachyptilaturtur settled on a patch ofdiscoloured water, which Observed once, on 16 June 1969. A group of may have been a surface shoal offish, to the 20-30 divedrepeatedlyintoaswarmofkrilllo- southofBlackRock. catedabout1.5kmsouthofBlackRockincom- SouthernGiant-PetrelMacronectesgiganteus pany with feeding Short-tailed and Fluttering Giant-Petrels were frequently seen offshore Shearwaters and White-fronted Terns. Speci- fromJunetoDecemberthroughoutthe40year men RW#414, collected 16 June 1969 (Mu- period, with a fewadditional sightings oflone seumofVictoria), amale,testes minute,heavy birdsinJanuary,February,AprilandMay.Dark- sub-cutaneous fatdeposits,stomach filledwith plumaged individualspredominated,withonly CoastalKrillN. australis. three all-white (June, September), one grey Short-tailedShearwaterArdennatenuirostris (June) and one pale-headed individual (June) in 157 sightings. Onlyone recordwas madein sThheeardwaaitleyrptaossaangde forfomlarbgreeendiunmgbecroslonoifesthoins thesecondsurveyperiod (June2005). the south-west and south coasts of Phillip Is- Despite Giant-Petrels being avid scavengers land was a feature ofthe offshore bird activity ofdead seals onmanysubantarctic seal islands fromOctobertoFebruaryeachyear.Thereafter and the frequent presence of seal carcases on tothebeginning ofMaythenumberand regu- Seal Rocks, only two instances of scavenging larity of sightings declined. Observations fell bySouthernGiant-Petrelswereobserved,on27 — intothreebroadcategories morningexodus May 1972 and 24 June 1972. However, Giant- andeveningreturn,localised activityatthesea Petrels were seen feeding on carcasses floating surfacewithin 3-4km ofSeal Rocks, andindi- offshoreonseveraloccasions,andoncetwo Gi- vidualbirdsatorcloseinshore. ant-Petrelswereobservedpaddlingaboutovera The morning exodus in calm to moderate concentration ofCoastal Krill Nyctiphanesaus- weather was an orderly stream passing East tralisandsmallfish,whichinturnhadattracted albatrosses,gannetsandothersmallseabirds. 8 TheVictorianNaturalist Research Reports Reefheading to the south and south-west; no FlutteringShearwaterPuffinusgavia movement to the south-east was observed. In Recorded on 16 occasions offshore in the first strong winds and heavy seas the birds were survey period, most frequently in June-July active offshore all day, widely dispersed on all and October-November, usually in groups sidesandseemedtocircletheisletsbothclock- of2-5 birds. On 3 November 1969 at least 50 wise and counter-clockwise. Landward move- were observed feeding within 100 m ofNorth ment in the eveningwas always diffuse. In flat Beach. Sightings inJanuary,AprilandSeptem- calm seas, large raffs (c. 300-500 individuals) berwere ofsingle birds. In calm weather feed- of these shearwaters were occasionally noted ing birds rose from the surface, flew a short about 3-4 km offshore to the south-east and distance and plunged in with wings extended. always inthesamegeneral vicinity. Duringthe Inroughweathertheywouldflyintothefaceof morning these raffs continually broke up and an oncoming wave, emerge from the rear and reformed nearby, but if present in late after- flyinto the next. Bydropping back 50 m orso noon they were more stable, with most birds with the wind after passing through a succes- resting quietly. Infrequently, large flocks and sion ofwaves the same general vicinity would smallgroupswereseenfeedingatthesurfaceto beworkedinthiswayforaboutanhour. Speci- the south-east, south and south-west. Tempo- mens RW#416, 16 June 1969; RW#449, 20 Oc- raryraffsformedwhenbirdsalightedovercon- tober 1969 (Museum Victoria). centrationsofkrill,dippinganddivingbeneath Common Diving-Petrel Pelecanoides urina- the surface. In January and February 2000, c. trix 3500 and 200 respectivelywere recorded feed- One record only, ofa desiccated carcass found ingwithinseveralkilometresoftheislets. intheenclosedSouth Plateau observationhide Crested Terns and Fluttering Shearwaters were occasionally seen feeding with Short- on26May1976.Ithadenteredviaanarrowgap MtaoisletduSnheexaprewcatteedrlsy,onatfheewsaSmhoertc-otnacielnetdraSthieoanrs-. MOinantyh2eo5frMSoaaonyfaR1te9ms7o6o,mReoMbtWsie,mrevoeandftbeaorwa7irddJealtnyhuedaiLrsoyprer1ra9si7e6n.de waters were seen in June 1969, on several oc- group of50+ Diving-Petrels offPyramid rock, casions during the 15th, 18th and 19th. The approximately 13km eastofSeal Rocks. context of these sightings was remarkable in thatthesebirdswereactiveonalargeswarmof LittlePenguin Eudyptulaminor Coastal Krill, together with Fairy Prions, Flut- Breedingwasnotobserved, butsmallnumbers teringShearwaters, White-frontedTerns,Silver came ashore to moult or rest or because they Gulls, Black-browed and ShyAlbatross, Giant- weresickorinjured.Moultingbirdswerefound Petrels and Australasian Gannets. However, frommid-Januarytomid-April,butassitesfree only the shearwaters, prions and terns were ofdisturbancebysealswerefew,themaximum feedingdirectlyonthecrustaceans. number of birds found at any one time was On rareoccasionslone Short-tailed Shearwa- eight. Moulting birds hid behind fallen boul- ter were seen resting on the sea, and in calm ders at the base of South Plateau and North conditionswerepronetoattackbypredators.In Plateau or in shallow caves, or took advantage oneinstancetwoimmaturePacificGullsrepeat- ofartificialshelteraffordedbyawoodstackand edlybuffetedtheShearwaterwhenitattempted a section offlooring stored under a cliffover- toliftoffthesurface,knockingitdown intothe hang.Foursinglebirdswerefoundmoultingin water. On another occasion two Giant-Petrels crevices around South Plateau between Febru- were seen tearing at a helpless bird floating at aryandMay 1997-2005. the surface. Despite opportunities for Austral- Penguins found atothertimesoftheyear(24 ian fursealstopreyon Short-tailed Shearwater alive, 21 dead) were all in light to poor condi- in nearby waters, no instances were observed. tion; in eight instances they were wholly or Similarly, Deagle et al. (2009) found no evi- partlystained byoil. Ayounglightlyoiled bird denceofshearwaters(oranyotherbirds)inthe found on 16 January 1973 was infested with a faecesoffursealsatSeal Rocks. large number ofticks attached to the back of Vol 130 (1) 2013 9 Research Reports its head and neck. Ten carcasses were found cm long were a common prey, and one other within tide reach and may have died at sea, fish taken appeared to be a Crested Weedfish but the remainder had died where they had Cristiceps australis, which occurred in the per- taken shelter. On 10 occasions, live penguins manenttide pools. When in thewaterthebird wereseen duringthedayamong fursealsrest- was extremelywary ofseals and when resting ingonMainBeachandNorth Beach, andwere alwayschosearockwellclearofthoseashore.It completely ignored by the seals, although the became noticeablyagitated iftheresident Kelp Cape Fur Seal A. pusilluspusillus and the New Gulls passed overhead, but tolerated the close Zealand Fur SealA.forsteriare known to prey proximityofotherrestingcormorants. upon penguins (Shaughnessy 1978; Page etal. GreatCormorantPhalacrocoraxcarbo 2005). Although in plain view of Pacific and Duringthe first decade ofthis surveythis spe- Silver gulls, on only one occasion was a pen- cies was a rare visitor, in spring and summer, guin harassed and forced to retreat to the sea. with only four sightings of one or two birds Penguinswereoccasionallyseenfeedingwithin m presentfortwoorthreedays. Duringtheafter- about 100 ofthe shoreandoftenwereheard noon of24 November 1976, 6-10 birds settled callingincalm,foggyweather. nearBlack-facedCormorantsonNorthPlateau FrigatebirdFregatasp. and towards evening a flock of60+ flew past; A single sighting, on 20 December 1968 by thelastand maximum countonNorth Plateau RMW and WMB. Shortly after 13.00 hr, atten- that season was 30 on 14 December 1976. Up tionwas drawnbya chorusofalarm calls from tofivewere recordedattheroostinNovember thecolonyofSilverGullsto adarkbirdpassing andDecember 1977andonetotwoinDecem- south overEast Reef. Although closelypursued ber 1978 and 1979. Singlebirds were recorded bythegulls itflewunhurriedlyofftothewest. onNorth Plateau onvisitsin October andNo- vember 1999andJanuary2000. AustralasianGannetMornsserrator Seen frequently offshore throughout the year, LittleBlackCormorantPhalacrocoraxsulcirostris but most often between November and Janu- Fourrecordsonly;ofasinglebirdrestingamong ary,andgenerallyouttoseawithinanarcfrom a group of immature Pacific Gulls on Main east to south-east or from west to south-west. Beachon23 October 1972,oftwobirdsresting Abouthalfofthe 151 recordswereoflonebirds near a Little Pied Cormorant and Black-faced and the remainder were ofgroups of2 to 30, Cormorants on Main Beach on 16 November usuallyflyinginlinesabreastortrailing.Imma- 1972, ofa single bird resting with Black-faced ture gannets in mottled plumage were seen in CormorantsonNorthPlateauon27December allmonths, alone, in pairs and inthecompany 2002, and a desiccated carcass on Main Beach ofadults. Feeding diveswereseen onafewoc- belowSouthPlateauon6January 1977. casions (see notes on Short-tailed Shearwater) PiedCormorantPhalacrocoraxvarius andinMay1999,groupsof20and30wereseen Sixrecords in January, March, August and De- feedingin conjunctionwithCrestedTernsand cember oflonebirds standing quietlyon rocks Silver Gulls, on clupeiod fish probably being close to thewater’s edge. One additionalsight- driventothe surfacebyAustralian SalmonAr- ingwasoftwobirdsthatperchedbrieflyonthe ripistruttaceous. steel flying-fox cable mid-way between the is- LittlePiedCormorantMicrocarbomelanoleucos lets,on7March 1969. Notrecordedinthesec- One bird, probably the same individual, was ondperiodofthesurvey. sighted on most visits through 1971 and 1972 Black-facedCormorantPhalacrocoraxfuscescens (26 records) and was usually actively fishing. In groups generallyless than four, rarelymore Lonebirdswereseeninfrequentlyin1969,1973, than 10, from February to November, roost- 1976,2001,2002and2003(12records).Fishing ing in the evening on portions of high rock activitywasconfined totheprotectedwatersof the landinggutter, Seal Pool and the deep tide emaasstspeosinnottofusBeldacbkyRtohcekfuarnsdeatlhs,ein.oe.rtthheesdoguetho-f pools at the south endofMain Beach. Juvenile NorthPlateau,withadistinctpreferenceforthe BluethroatWrasseNotolabrustectricusupto 15 10 TheVictorianNaturalist Research Reports latter. In December to Januaryover seven sea- SwampHarrierCircusapproximans — sons(1966-1972), numbersincreasedtoanav- Fourrecordsofone ortwobirds passing on erageof26and32respectively. Amaximumof 4 November 1969, 25 July 1971, 21 September 67 was recorded on 14 December 1977. In the 1971 and 18 January 1973. The resident Silver second survey period, numbers ranged from Gulls were greatly alarmed when they flew 0-57 andaveraged 11.7. overhead and on one occasion a pair ofnest- On North Plateau they invariably roosted in ingKelpGullspursuedaloneHarriersoclosely a group along the northern edge, spaced uni- that it was forced to flip and present its talons formlyabout 1 mapart, standingorsleepingin to break up the attack. The July record was of anuprightposture. Individualssometimes tore a lone adult flying slowlydue south and stead- up abandoned Silver Gull nests ofdried noon ily gaining in altitude until outofsight. A fifth flower stems, tossing beakfulls ofthe material recordwasofalonebirdperchedonawooden intotheair.Theirroostingareabecameheavily planknearthefieldstationon 13August 1969. fouled with white guano splashes during sum- NankeenKestrelFalcocenchroides mer and encroached on nest sites of Crested Sixsightings inJanuary(1966, 1968and 1972), Terns, Silver Gulls and a pair ofSootyOyster- and single sightings in April 1966, September catchers. Some birds were occasionally seen 1968, November 1970 and June 1972. All were fishing in open waters near shore, but never oflone birds either perched on cliffledges or in the Seal Pool or in the deep tide pools on the railing of the observation towers upper MainBeach.Disgorgedfooditemsfoundinthe deck,orhoveringovertheplateaux.On 19June roostingareaonNorthPlateauincludedasmall 1972alargefemalewasdisturbedfromthecar- leatherjacket (Aluteridae) and an Australian cassofaCommonStarlingfromwhichmostof Salmon. the flesh had been stripped. She later returned CattleEgretArdea ibis andcarried offthe remains. Later that daytwo Single record ofa solitary bird on Black Rock otherpartlyconsumedStarlingswerefoundon on 13 April2000. MainBeachandSouthPlateau.Thehindendof a small rat (possibly Rattus norvegicus), found White-faced HeronEgrettanovaehollandiae on North Plateau two days later, had probably Thirty-onerecords,mainlyoflonebirds,butalso been carriedtotheisletbythisKestrel. ofgroups ofup to 10 in summer and autumn duringperiodsofcalm weather. Abouthalfthe BrownFalconFalco berigora sightings were ofbirds flying past directly to- Four records; two birds on 20 January 1966, wards Phillip Island or north-west. Those seen and lone birds on 26 February 1966, 17 Janu- onshorechosetoroosteitherontheplateauxor ary 1972 and 17 November 1977. On the first outerreefareaswellclearofanyseals. three occasions the birds remained high and showed interest in the activity of Silver Gulls RoyalSpoonbillPlatalearegia and Crested Terns below, but they eventually One sightingofalonebirdon27January 1966 flew offtowards Phillip Island. On the last oc- thatcircledaboveSeal Rocksseveral timesand casiontheFalcon tookaSilverGullchickfrom thensettledbrieflyonEastReefbeforeheading West Beach and flew offto the north-east. Al- north intoalightnorth-easterlybreeze. thoughthegullcolonywasgreatlyalarmed,the White-bellied Sea-Eagle Haliaeetus leu- Falcon wasnotpursued. cogaster PeregrineFalconFalcoperegrinus One sighting on 16 November 1977 ofa lone Four records, possibly ofthe same bird, on 2 adultthat madealowleisurelycircuitoftheis- and 10 November 1970 and on 9 and 15 Janu- letsfollowedbyamobofscreamingSilverGulls, ary1971 circlingtheislets.Onthelattertwooc- tphraotbawbelryeoantetohefapepaaikrorfesniedsetnitnga.tTFhriesncbhirIdslwaansd cPalsaitoenasuibtywaasmdorbivoefnSfirlvoemrtGhuellvsicainnidtyfloefwNoofrfttho andoftenseen inthevicinityofSandy Point 17 theNobbies,rousingthegullcolonythere. kmtothenorth (DavisandReid 1975a). Vol 130 (1) 2013 11 Research Reports Australian Pied Oystercatcher Haema- apparentlybecausethefirstchicktoemergewas topus longirostris moved by the parents a—nd the second eggwas Twobirdswere sighted on4 and 16November abandoned in the nest a sequence observed 1969 andlonebirds on 7 October 1970 and 15 intwoinstances.Ofthepossiblemaximumpro- November 1972.Allrecordswereofbirdsmak- duction of25 fledged young bythe North Pla- ing several circuits ofthe islets beforeheading teau pairs only 14 large runners’ were actually off towards Phillip Island. On one occasion found, partlybecausetheparents wereadept at twobirds settledon East Reefbutwerequickly hiding them in crevices andnarrowspacesun- driven offby a resident pair ofSooty Oyster- derboulderswheretheirplumageblendedper- catchers. fectlywith theblack basalt. When we searched fortheserunnerstobandthem, aparentwould SootyOystercatcherHaematopusfuliginosus occasionallyresorttoa‘brokenwing’displayto Threeresident pairsroutinelynestedontheis- luretheintruderaway. lmetusmthrnouumgbheorutrbeoctohrdseudrvweayspenriinoedso.nT2h5emOacxtio-- The success ofthe Black Rock pair was very difficult to follow, but in the five seasons prior ber 1999 and there were lesspresent inwinter, to being ousted bythe Kelp Gulls in 1972 they usually four to six birds. The mean (±_s.e.) of hatchedatleastthreechicks.Inthesevensubse- 39 counts in the second surveyperiod was 2.6 quentseasonswhentheynestedonthesouthern (±0.37). Until thearrivalofapairofadult Kelp ‘toe ofNorthPlateauonlyfiveclutcheswereseen Gulls in late 1970, two pairs nested on North (3x2eggs,2x1 egg).Inthesummerof1973/74 Plateau and a third on Black Rock plateau. In the Kelp Gulls abandoned Black Rock for Seal subsequent seasons the Kelp Gulls ousted the RockandtheOystercatchersreclaimedtheirold latter,atatimewhennestingbytheotherpairs nestsite.Theywerefirstseenthereon10January was well advanced. The ousted pair then es- 1974andfour dayslaterthe nest containedone tablished anest on the southern ‘toe ofNorth egg. The fate ofthis nesting was not observed. Plateau, on two occasions appropriating a Sil- Forthefirstfourtofivedaysafterhatchingchicks ver Gulls nest. The North Plateau pairs were werefedsmallinsectsandarthropodsprobedfor aatgglreeassstiv3e5lymtearpraitrotr.iaDl,ureisntagbltihsehienngtitrheeisrpannestosf bchyitchkesirrupnanrienntgsfirnotmheonmeattostohfenootohnerfwlohweenr,evtehre 14 years these nest sites shifted by only a few somethingwascaptured. Thereafterchickswere metres. Nesting Silver Gulls were tolerated to fedwith theflesh ofchitons, smalllimpets, and wwietrheinc3ommm.oInnt,er-anadndthientrlaasttpeerciwfiecreinteesrpaecctiiaolnlsy uthneivoaultveergianstterr-otpioddasl z(NoenreistaofspM.)aignarBneearcehd,fEraosmt ciennttelnysehawthcehendpaanrdenhtisghwleyrmeobatitleencdhiincgk.thOenirornee- ReAedfulatndOMyisdtedrlceatRecehfe.rs were extremely sensi- occasionasittingoystercatcherleaptup,caught tivetothepresenceofhumansandimmediately ahnaddvthernottutrleeddtaoroecneenart.lyTfhleedGgueldlSwialsvehreGludlldothwant vTahcisateisdsaimnielsatr tifoatphperoflaicghhtedintiotiawtiitohnindis5t0anmc.e by a beak hold behind its head, the Oyster- reported forthisspeciesbyGloveretal. (2011). catcherstandingmotionlesswithitsfeetbraced Despitegreatcaretominimisedisturbance,this wideapartuntil theGullwasdead. wasundoubtedlythecauseofsomenestfailures In13seasonstheNorthPlateaupairsproduced asSilverGullswerequicktoplunderaneggand at least 25 clutches (14 x 2 eggs, 5 x 1 egg, 6 x were suspected oftaking at least one exposed eggsnotvisible). Onfouroccasionstwoclutch- newly hatched chick. It is likely that the poor eswerelaidinaseason,threeafterearlyfailures, success oftheBlackRockpairwhennestingon andin eachcasea chickwasrearedto fledging; North Plateau was exacerbated by their close in the fourth instance two eggs were laid af- proximityto thefield station locatedonlyc. 40 ter the fledging or loss ofa near-fledged chick maway.Oneoftheserunners,bandedonNorth (c.42daysafterthefirsthatching),butthefateof Plateau5January1977,waslaterfoundasades- the secondclutchwas notobserved. Inno case iccated carcass on Forrest Caves beach, Phillip ofclutches oftwo eggs were two chicks reared, TheVictorianNaturalist 12 Research Reports Island on 24 April 1987. Another, banded on FairyTernSternanereis NorthPlateau4January 1980,wasseenatLong Twoorthreebirdsseenoffshoreonthreeocca- Island Point near Hastings on 1 August 1981 sionsbyKJCinlate December 1965 andalone andwassubsequentlytrapped thereon 12 June birdon 17Januaryl966. 1988and released. Two resident colour-banded CaspianTernHydroprognecaspia birds in the second surveyperiokdmwerebanded Recorded only once, by KJC on 31 November rtewsopeycetairvseleyarlaiterFlainnddeirnsC(ocr.n1e0rInletn(ocr.th1-2e5akstm) l1a9n6d8edfeeodninNgoorftfhshoPrlea.teTauh,ebTuetrnflseuwbsoefqfuwenhtelny south-east)sixyearsearlier(asatwo-yearold). alertedbyalarm callsofSilverGulls. MaskedLapwing Vanellusmiles White-frontedTernSternastriata ApaironBlackRockon 22 January 1968. One CommonlyseenfromlateApriltomid-Novem- heard by KJC calling during night of 21-22 ber feeding offshore and often diving for small August 1969. fishcloseintotherocks,intheSealPoolandin RuddyTurnstoneArenariainterpres the shallowlanding gutter. Often roosted over- In the first survey, RuddyTurnstones were ob- night on Seal Rock, generally in groups ofless served on allvisits except during the winter of than 10,butoccasionallytherewere50.Theyin- 1969. From MarchtoAugusttheywereusually termingled freely with roosting Crested Terns. seen in groups of5 to 10, their numbers then On 16June 1969White-frontedTernswereseen increasingsubstantiallyto about50 in Novem- divingintoaswarmofkrilltothesouthofBlack ber to January. A few birds in richly coloured Rock, where FairyPrions, and Short-tailed and plumage were seen in April, July, August and FlutteringShearwaterswerealsofeeding.Speci- September. In the second part of the survey, men RW#415 (Museum Victoria), stomach numbersrangedfrom0to 11 andaveragedtwo contained Coastal Krill; subcutaneous fat light birds per visit. Turnstones were observed on orange in colour. This species was not seen on only47% ofvisits inthesecondsurveyperiod. or in thevicinityofSeal Rocks duringthe sec- Dispersed groups were often seen feeding ond survey period but has been recorded oc- along the shoreline at low tide, among weedy casionally along the southern coast of Phillip rocks and over beds ofcunjevoi Pyura sp. Oc- Island (Norman 1992) but not in Western Port casionallysmallflockswereseenmovingabout between 1991 and 1994(Dann etal.2003). on, and the slopes above, the Main Beach and CrestedTern Thalasseus hergii twiceonSouthPlateauamongclumpsof noon BeforethefieldstationwaserectedontheSouth flowerwheretheyappeared tobesearchingfor PlateauinDecember 1965,40nestswerefound insects. Towards evening and during strong on a narrow band of noon flower growing at wpairntdssofthtehyecsohnogrreegpalattefdortmosraoonsdtoifntesnhealmtoernegd thecliffedge,andatleasteightpairshadnested onthenorth-west cornerofNorth Plateau.Af- the fur seals, where they moved about confi- ter 1965 all nesting activity was concentrated dently and were totally ignored. Turnstones onNorth Plateau,butonly20nestswereestab- wereoften seen resting inveryclose proximity lished. The output ofthis colonywas about 12 to PacificGulls. young/yruntil 1971/72whentheentirenesting ArcticJaegerStercorariusparasiticus was lost due to unusually heavy seal traffic on Thirteen sightings were logged ofone to four that plateau. In 1972/73 only three nests were individuals active offshore during spring and foundthere,buteightnestswereestablishedon — summer from October to March in the the upperboulder slope ofWest Beach among first survey period. Most often they were no- nesting Silver Gulls. During the next four sea- ticed in November to January, when pursuing sons(1974/75to 1977/78)nestingwasconfined Silver Gulls returning from Phillip Island or to West Beach, but the maximum number did the Mornington Peninsula with food for their not exceed six. In 1974/75 and 1977/78 two young. Vol 130 (1) 2013 13