Corella,2004, 28(1): 24-30

RECOVERIES,RECAPTURES AND RESIGHTINGSOF AUSTRALASIAN GANNETSMorus serrator BANDEDAT LAWRENCEROCKS' VICTORIA

F. I. NORMAN' andC. COOPER'z

rArthur Rylah Institutefor EnvironmentalResearch, Department ofs{stainability and Environmeot,123 Brown Street,Heidelberg.

2DeDartment of PrimaryIlldustrv, 8-12 Julia Street,Portland, Victoria 3306

Received:13 January2003

Bandingof Australasiangannets Morus seralor (mainlyot pre{ledging young) at Lawrence Rocks' off western Victoria,w;s initiatedin 1960 and continuedin most years until the 1971-1972 breeding period; a second series ol banding began in 1986-1987 and occurred annuaily until 1996-1997. A total of I640 young and 374 adults was bandid during these visits. Recoveries,recaptures and resightingsof these banded birds are summarised here. To June 2002, some 203 12.11")ol birds banded aS young have been recovered both locally and at considerable distances. Dispersai tended to be westwards and included numerous records around Western Australia;younger (<48 months) birds were often recoveredat greate. distances.For younger birds, recoveries were more numerous in months immediatelyfollowing fledging whereas older birds (>48 months) were usually tound within the breedingperiod. Between 1960 and 1997,86 birds markedas chicks were recapturedat Lawrence Rocks, usually lour or more years post banding and breedingwas increasinglyleported in birds over.threeyears old. Two bird; from Lawrenie Rocks were lound dead during developmentof the Wedge Light colony in Port phillip Bay, and 12 others have subsequentlyentered breeding populationsthere although only three lrom Port phillib sit;s have been recorded at Lawrence Rocks. Several birds banded as chicks have been recovered (or resighted;at the newly-establishedmainland colony at nearby Point Danger and il is suggested that this colony was founded by young breedersfrom Lawrence Rocks.

Bandingbegan at LawrenceRocks as the colonywas expandingand continueduntil the site was fully occupied. The record;d itrusion of birds from other sites has been low and it is considered that the colony developed essentiallyfrom the return of birds to the natal colony (apart from the inclusionof a small number of Cape gannets M. capeisis now breedingthere). Since Australasiangannets may move extensively,particularly when young and not bie€ding,conservation measures must lake account of its temporaldistribution and requisiteresources

INTRODUCTION generally.Locations of Victorianbreeding sites were given in Norman(2001). Colonies ofAustralasian gannetsMorus serrator (garnets below) have increasedrecently, both in size and number, METHODS in New Zealandand in Australia(Waghom 1983;Hawkins 1988; Norman et al. 1998l-Bunce et al. 2002). For Stud! sie and Tkrtt devebpnv example,colonies in Port Phillip Bay haveexpanded from Lawrence Rocks consist of two small, low lying volcanic islands 01 one site first occupied in 1966 (Wedge Light, 38'16'5, approximately 6.8 and 1.5 hectares about 2 kilometres off Poini Dangcr, 144"42'E),to eight in 2002. This growth has occurred near Porliand in westcm Victoria (for the location of Lawrence Rocks. 2001). The islands, separaledby mainly as a result of internalrecruitment, although some and other Victorian sites, sec Norman of open waler, are about 90 met-resand l0 metres above (38"25'5, until abou{ 50 metres birds from Lawrence Rocks 14l'40'E), mean sea level respectively (Pescotl 1980 provided some further details) recentlythe only other breedinglocation in Victoria,have Early records(Grant 1803iBonwick 1858)implied that rclativelysmall intrudedinto the populationbreeding within the Bay (e.g numbers of gannets bred on the larger island in the nincteenlh century. In 1900 there were some 200 nesls present (w' Maccillivray in Norlh Norman 2001). The increases,at least at Victorian sites, 'attendrng (bu( nests)were have taken place in a period when local sea surface 1914) and in 190? about 400 birds <200 their younS on (he summit (Ma(ingley 1908, 193'1).An acrial survev temperatureshave risen and trawl fisheries have expanded, in March 1943 suggestcd thal there were 190 nests: while there werc potentially generatingfood as a bycatch (Bunce e/.r1. other obscrvalions towards the end of, or oulside, breeding periods' no 2002). For much of the period of growth the commercial estimates were made but Fowler and Serventy (n.d.) considercd thal the pllcha'd (Sardinops sngax) fishery also increased, colony at that time was being limited by factors olher than human l. watson (unpublish€d dala, Departmcnl of Natural particularlyin Port Phillip Bay, althoughboth total catch interfcrcnce. Resources and Environment (DNRE) file 86907) obscrved 603 nesls in and catch per unit effort declinedsubstantially following Novcmber 1958,McKcan (1966) reportcd406 breedingpairs in 1952, massivemortalities of pilchardsin 1995 and 1998 (e.g. 605 pairs in 1960 and 639 ir 1961, and Harris and Norman (1981) Neira et c/. 1997;Coutin 2000; Gaughan2002). recorded 1 456 occupied nests in l9?8. Somewhatlater, Fisher and Cooper (n.d.) considered that there were I 474 breeding birds in 1980- The colony at LawrenceRocks has also expandedand a 1981, 2 463 pairs in 1987 (E. J. Wingham in Marchanl and Higgins new breeding site was esrablishedat nearby Point Danger 1990) and 5 490 i 150 adult birds'in Decernber1993. The colony the nesting area in 1995 (e.g. Norman e1al. 1998; Bunce et al. 2OO2).ln expanded onto the smallcr island in 1994-1995, and probably occupied in aroutrd 1996 (Norman It dl. from banding was completely this note we examine some results obtained 1998). Some 6 200 birds were counted in December 1996, al a time activities conducted at Lawrence Rocks and consider them whcn the colony at nearby Point Danger was developing (Norman It in relation to colony developmentthere and in Victoria d/ loo8). During rhr expansionof the LawrenceRocls gannelcolony. 25 March,2004 E l. Normanand C. Cooper.Australian Gannets at LawrenceRocks

Cape gannets M. capen[is were hrst recorded in February 1992 (lhrcc RESULTS birds), lwo were present in January 1993, four were seen in 1993-1994 (when one pair was [es!ing), sevenin 1994 (Fisher and Cooper nd; Banding totals chick bandcd January 1995), and four nests were found h 1995 1996 (two young banded). Bandingtotals tbr breedingperiods between 196u_.1972 and 1986-1997are summarizedin Table I In this time' Bt\,li\\. r, p|tt('. r,\rJ/rft,rs.,r,Jr,,,,crr,' banding took place in 20 of the possible 23 breeding Brnding of ganncts at Lawrence Rocks wls initialed by G Bowker periodsand 9 6,10young and 37,1adults were marked.A and J. McKean in 1960,and contrnucdby a small gtoup until lhe l97l further 28 birds had bands replaced between I986 and break. E Waghornbcgan 1972 breedingperlod. Afler a considerable adults were bandedbetween the more recen!series of bandingsnr the 1986-1987breedinS pcriod. 1997. tt is clear that more rnd rhis was conlinucd until 1996-1997 by C Cl. Aluminium bitnds 1960 and 1972 than subsequentlyand that a higher rate irerc used in the first scriesof bandings,but slainlesssteel bards (all of bandingper breedingperiod (almostentirely of young issucdby thc AustralianBird and Bat Brnding Scheme.ADDDS) wcre birds) was achievedbetwccn 1986and 1997. uscdsubsrque tly. In both pcriods.one or two visits $'cre made to the pre fledging colony in most breeding pcriods and large numbcrs of Re c0 pture s artti r esi g irtir g s gannets bandcd: v)me .rdults wcrc also mafked ln hlcr vrsils prrricularly.some alrelnprswere madc to capture freviously banded lletween i960 and I997, 86 recaptures of birds adults.(o rcplaccworn bandi and 1o obrrin band numbcrs. previousiy bandcd as young wers rnade at Lawrence In this study. barding totals havc becn dcrivcd trom micfofiche Rocks.The recapturetotal includes22 birds (1.2% ol the resighlingrnd rccordsor electronicfiles held by thc ABBBSTrecaplure, I 86? banded as chicks) from the first banding period fcpraccDrenrdctails have in generalbeen obhined froD ATJBDSand DNITEfiics Rccordsof bandedbifds found away from Lasrcnce Rocks which were recaughtin the second(no birdsbanded in the wcrc usurllv submiltcddircctlf 1|)lhc AIllllls aod this irfornlalion has 1966 1967breeding perioci were recaptureti).While small .rlsol)een compiled logcther wrth associateddelails available on DNRE numbers (n = 6. 7'/r) wcre present when two or three processed rilcs. Hcre sc rncludedaia rcceivedand by rhe AufltsS up yearsold, reDresentationtended to increasesubstantially to 30 June 1002 for.irvears atier bandrng (12, 13.9c/.)and subsequentiy For thc purposeof analysesbelow, rccovericsrelale lexcepi whcfe (Table2). More precisetiming oi retun Io the naralcolony odlerwis€indicated) ro the reporringof birds fou d dead.eirher al the ',vasprecluded by the almost annuai nature of visits tcr bandingsrte or clsewherc.Rrcaptures hcrc refer 1o the handlingof bifds oicliousiv bandcdal La\rreocekocks- a tinre NhcD lhc olsinal band tirc Rocks. rlirv rlso hlvc bccn repixccd.Occxsron.ri band numhersof some birds r,erc obtitined. particulrrl! rt jitcs aw.rv froIn Lawrence i\ocks. as Firds bandedas adultswere also recapturedor resighted i.sightrngs b) use oi binocuiar! li should bc roprecialcd thrt lotrls ar i-arvrenceRocks. between I I and 312 monthslater. and givcn beiow may vr.v bolh rs a resullof diflenng levelsof informalio0 athersnave also beenrecaptured elservhere. Thus one was ovided (parrlcuiirly rclatinr to rccovrfirs). aod as a consequcnccol L:lught anri reieasedoff WesternAustraiia during tuna pfoblemsol rcconcihg grlc rumberswllh iriinur0gs.They arc Drc\ious fisiring .,,rer (one Lhcrcr'orcnrnima. It should aiso bc nolcd ihat rccover.t-delails have been operaur.lns.two e caught cxhaustco')anci iricD rs givcn (r e. d.rlesof rccovcr-"hlvc bccn acceDreoas datesof dc h releasedand anothcrdicd whiJebeing rehabilitated. In .rlthoughlhev rnay xavc occurred some (pcrhirDsconsrdcrabb) time additron.lwo brrcis(bancied as chicksin the 1965-1966anci c:irircr)irnd rxlo nafiou rcgrrlirrg the ciiuscol dcarhrs l.rrel! alailablc :?56-1967 creedingperiocis) rvere shot at WedgeLight in l):stanccs and drfectrm fom thc brndrnq srte used bere are as !rcvrdcd r^o Phiilip Bay in February1972. 1.yAIlilllS and time eiaDsedsrnce banding is givenlo {hc neafestnxrnrh. Subsequontly12 other oircishrve the breedinupopulations in Port Phillip I.rsing lorned biil mersurcn1cntsofchicks rl Lawrc cc F.ocks_[ J Wingham llay ( 10 at Popes Eye. and one eacirat Point Wilson anci waghonr) calculatcd lhar h!ing rn 1986 i= l9t7 rungcu ffom 2{) i SouthChannei markcr), being recovered(l), S.plcrnbcr to ll November.$,irh the medlan drre bcrDg ll Octobcr recaptureo {j)NItE ,llc 86907). Neverthclcss.since inri)rm.rrrolrrcAarding mosr anci or resishted(li) there. This immigratronirom bLecdrng c!cDts is un.r!all:rble io. thc Lisrence llock! coiony, Lau,renceRocks occurredat low but simiiar ratesfor both !,r.!ririi/cd del.rilsfor the Popcs llrc rrd wedse Lighl coloDlcsin ll).t bandingperods (i.e. 0.1q,),invoiving two birdsbanded PhilliD iliry .rreused bclou rs .r oroxy. Ihus cgg laying is assumcdto between1960 and 1972and l2 of thosebanded between commencc in Seplembcrand fledging in Fcbrurfy Gee Norman rnd .!acnkhorsr i986 and 1997.The avcrugetime bet\\,eenbandrng (as l915 rbr dcrarisr. Jlthouch rt is r!alized thar solnc '',oungi rrtcraDnualvrfli ron occLfs (c.g. (]ibhs .r d1 1000: Itun$ 2001) and rccovery,llrst resiChtingor recaptureat Port

IABLE I ErDdine of Austrrlasian gaDrcts Mdrrr !zrfdn)/ al Lasrencc Rocks. Vicroria, 1960 1997.

Brnding Totals ToLils 1960-1961 2',79 62 34t 1986-198? 512 512 l96l-1962 329 3 332 I987-1988 383 389 1964-t965 20 20 19881989 6.10 640 ,7 1965-1966 2l I 8 zt9 1989-1990 978 985 1966-1967 288 102 390 1990-1991 I 014 8 | 022 1967 '7 1968 369 61 436 l99t-1992 65 8 713 r968-1969 39 6 45 1992I993 980 I 98r t969-1970 201 26 230 1993-1994 994 4 998 t91t-tg't2 128 94 222 1994-t995 519* 519 t 995-1996 488** ,188 t996 t99',7 500 500 Torals I 867 368 2 235 ? 807 * or ** = includesI or 2 youngCape gannets. E L Normanand C. Cooper Auskalian Gannets at LawrenceRocks Corella28(1)

TABLE 2 Recapturesof Australasian g nlsetsMorus setralor at l-awrence Rocks, Victoria, previously banded there as young

Banding 22- 35- 4a- 59- 7l- 83- 92- 240- 252- 264- 288- perrod 25 3',7 49 61 73 84 96 108 120 132 180 216 228 241 253 265 289 300 325 348 Total 1960-1961 14t3 I 10 1961-1962 2226 t2 1964-1965 l 1965-1966 lll 4 4 1967 1968 211 '7 1969-1970 151 '7 21 21r t91t-1972 'l 1986-1987 t 9 1987-1988 ) 133 10 1988-1989 z l0 1989-i990 5 2 1990-1991 2 I 1 12 ll 9142

Phillip Bay coloniesfor these12 birds was 89.8 (i 51.69, (8 126 km, 27 days after banding in January 1997). In 23-178) months although they may have occurred there addition, occasional birds have been recovered in earlier. Tasmanianwaters and one moved north of Townsville (Queensland).Movement, as indicated by recoveries,while On occasion,and particularlyduring the secondseries affected by coastline (and perhapshuman distribution), of visits, some note was taken of the breedingstatus of tended to b€ westwards.Thus of 176 recoveriesof young individual recaptures,but again the distributionof such gannets,99 (55.6Vo)were made between 270" and 0' and recordsreflects the timing of visits to LawrenceRocks. '77 (43.77o\between 0o and 135", Nevertheless,one bird was first reported as breeding when threeyears old, nine (17.67oof the 5l records)when four, Dispersal of young ftom Lawrence Rocks may be and others subsequently(Table 3). substantial(Table 4), with numerousrecoveries being made in WesternAustralia (see also Fig. l) but there were many at or near the natal colony. Thus, for the 175 birds banded TABLE 3 as young and found at known distances (and time) away Ages at first recorded breeding of Australasian EannetsMorus ierrator from the Rocks. 24 (13.11") wete tecoveredwithin l0 banded as young at Lawrence Rocks. Vicloria. kilometres and 37 (2LlVo) up to 50 kilometres.Movements (as indicatedby recoveries)were most extensivein the Banding Number breeding in ycars post banding younger age groups, pafticularly those less than 48 months 5 6 7 8 9 l1+ old. Hence, of 89 recoveriesinvolving this cohort, 2l (23.67o\ were made within 50 kilometres of the natal 1960 l97l | 2 I 18 22 1985-1997 19151 29colony,another 3I (34.8ok)within 500 kilometresand 37 (4I.6Eo) beyond. Although a similar proportion of the 86 l8 5l recoveriesmade of older birds were within 50 kilometres of Lawrence Rocks ( 16, l8.6Eo), 62 (72.170)were reported between51 and 500 kilomebes and only 8 (9.3Vo)were Recoveries more distant. The difference between the groups was significant(X'z = 29.655,df = 2, p < 0.0001). To the end of June 2002, there have been 203 recoveries of Australasiangannets banded as young (i.e. 2.lqo of 9 There is some indicalionlhal recoveriesare more as young, in the months 640) at Lawrence Rocks; the recovery rate for birds banded frequent, for birds banded following fledging.Of 75 individualsrecovered within l2 as adults (374) was somewhathigher (12,3.29o). Rates 26 (34.77o) were reported between varied for the two banding periods, with 57 (3.07o)of those months after banding, March and June (Table 5); others were found dead at chicks banded in the early period being recovered (25) visits in comparedwith 146 (1.9olo)for the later group,presumably LawrenceRocks during routinebanding the December-February period, or elsewhere throughout the reflecting the shorter time available for recovery of birds year. For birds of breeding age (here taken to be banded in the second period. >48 months old, e,g. Norman and Menkhorst 1995) the The locations of recoveries of gannets away from situation was significantly different, with more recoveries LawrenceRocks are summarizedin Figure l. Clearly many (including recaptures and resightings) being made in the birds were found dead locally, around coastal areasof breeding period. Thus of 88 recoveries(including l0 western Victoria and southern South Ausbalia. However. resightingsor recaptures)only 19 (21.6Vo)were outsidethe otherswere more distant;recoveries in WesternAustralia assumed September February breeding period ()P = were not uncommon and one was made in Mauritius 28.409,df= l, p < 0.0001). March,2004 F.I. Notmanand C. Cooper.Australian Gannets at LawrenceRocks

10

20

Fi9ve l. Lcatiotlt where recor,e es of Auslruhsian 8ailpLr Morus serrator bdnAed at lt\trence Ra,aJ, Uctoria v)ere made around coa\lal AusttolLa. (Posilion of l^xwrence Rock indicated Iry am)w 150 and latitude'S and loneitude'E sho*'n. Multiple rerords ar mdividual ttc\ an not shoqn, @r it the one recovery in Mauitius).

Details for causes of death of recovered gannets are four were consideredto have been killed by predators infrequently available (or determined). For the 203 (three at the Point Danger colony). On some banding visits recoveriesconsidered here, the majority (187,92.17o) were to Lawrence Rocks, young (not necessarilybanded) were 'fly merely reportedas dead, with no indicationof the cause reportedly affected by strike'. Although its extent and of, or time since, death. However. one bird was recovered importance is unknown, some 20 chicks were dead and a from the stomach of a white-pointer shark, five were similar number infected in early 1987; another22 were 'lot'of caught in hshing gear (one released),one was found near reporteddead later that season.There were a dead overheadwires, another was tangled in a tree (at Point chicks found in December1967 and some l2 chickswere Danger), two were shot (at Wedge Light), one spearedby also tbund dead in February 1990, though causeswere not an arrow, one became caught in fencing (Pope's Eye) and determined.Based on recoverydates, there is no evidence

TABLE4 Distancesof recovcries(including recaptures andresightinst of-{ustralasianasanners at LawrenceRocks. Victoria. (Birds recaprured, fi:i:r.::,Ja"J;r:

Age at recovery_ Disrancc of recovery (km) (months) _ o ffir-rooo l00l-l 500 l50l 2000 2000+ O :t8 I 14 6 2 5 89 48 {0 I 2 I 't I I I I ?3-84 4 2 4 l0 85 96 2 2 6 2 l5 97-108 2 4 8 I09-120 l I 6 t2t-t32 I 133-144 I I 145-156 I l 5 157-168 l 5 169-180 ) 5 181-192 I I 193-204 I 205-216 I I >211 I

l3 l5 175 F l. Norman and C. Cooper.Australian Gannets at Lawrence Rocks Corella28(1)

TABLE 5 Month of recovery and time elapsedsince banding for Australasiat g nters Motus serraktr banded as young at lnwrence Rock, Victoria. (Numb€rs in parenthesesrefl€ct resightrngsor recaptures).

Months since Month of recovery banding M '75 0- l2 4 I 921 8 8963 t3-24 2 4 (1) 3 I 11 2 l5 25-36 I 4 tl 12 3',748 I (l) t 3 I I 8 49-{0 3 2 2 (t) ll 9 6t-12 2 (l) 2 (l) l I 3 (l) II 't3-84 4 1 I (l) 9 85-96 2 (l) 2 (l) 4 3 I 15,| 2l 97,108 I ,7 109120 t2l,t32 ll 4 t33-114 I I 145-156 I (l) I 5 l5?-168 2 5 r69 180 I (l) I 1 (1) 5 l8l-192 I 2 193-204 1 205-2t6 1 >2t'l I

Totals 1(2) l0 (3) 11(2) 28(1) 2s(t) 37(1) 23(2) l4 16 r0(l) r98

that the mortalitiesof pilchardsthat occurredin 1995and representingabout six per cent of resightingsof banded 1998resulted in increasedgannet deaths at thosetimes. birds, it was consideredthat colony growth essentially resultediiom internalproductivity (Norman 2001). Indeed, Gannetswere recoveredalong the coastlinenear Point the representationof birds tiom LawrenceRocks at Port Dangerthroughout the study period and, sincethe colony Phillip Bay sites decreasedas the coloniesthere grew.It developedthere in 1995,five bandedas chicksat Lawrence is of note that the colonv at WedgeLight in Port Phillin Rockshavc been found dead in and aroundit. Two of these Bav was begun(in 1966)at a time when that at Lawrence recoverieswere made2,1 and 25 monthsrespectivelv atter Rocks $'as expanding,the Pope's Eye colony was also bandingwhile the othersuere 77. or morc. monthsold. A irbout 1985)welt the Rocks was bird was also resightedin lhe coiony 68 monthspoil established before colony Danorng. comolere.At LawrenceRocrs. as at Port Phillip Bay sites (Norman2001), return ol previouslybanded birds was DISCT]SSIOI': increasingly recorded fiom their fburth r'ear onwaris y,lunger 'ihe although biios were occasionaliisllcn. Such hiros qanneicolonv iit La$renceRocrs rentarrrecsmaii wcrepresLrmabty rcsoonsrbie tur colonvdsvclopment at aii rno rt aboutthe snmesize irom *'sll ceiorel90ir io th; sitesLsee ais,.r Wo.lzici; 1967'.ilo conjidered.nat mL ' i9.i0s, but ir hrd Counleclb\ i9)l rno ircreased ret.;rrrrJ u l:el substantrlllybv the i960s.lVhcn ban.inc\tas initiared t: oi orros iilrn Lt*rerce ilca,is iii nearb],iroirt D:lnge- Llwrenae kou.s in l95u rn:re \\ere sonte60C brcciing (whichdevelopecr rrom i995 on\\'ards,dbout tne time !"5:- DairsiN'lai.',eirl irLr6l. a Dooulatioiilthich nao croanilcq Llwrcnc: Rocks *eie lu!l-r'ocrupieJ: lorrnan c: a.'.199,- to o\ei 2 40,Jpari' br l9ti7 rand mcrc tatei)rvhen the ilu:rai .r/ al. 20(lll rncl;:ite.ir!re rmponiincecf rhc seconobilfdi.g nqrr.clw1s unlerw:iv.Somc oir'dsbancjec i,awrencr:kocxs {roionvas a souiia of breedlt:gbi.-.- ] perirrci jn rs chlcks rn lh! cailiar r.ere iecapriircd Lr- Poin, I)rnger (ro rllnough soine birds qcre see:,()1 seconopenod. indlcailni']! rerllrn to tne nil,,alirr)r0n,, ano recolercd theic whcn aDout t\r'o years oii, others u:-,- a phrrooatrysimilai to that prevlJusii'reoortecr in thrs aiir older whcn resightecior recovered.As ihe colony al (e.9. closelyrcrarcd soecics Nelsoni97E; Norman20011. l,awrencei).ocks lilled, oDDortunit]eslor voungerblrds:- While the rateoi this rcturnto the natalcoi0n1, rs unknoq'r oreed presumably dccreased u,hereasthev had bee. at Lawrcnce Rocks. elsewherclt cln be extensiveanci, gnnancedt3s at Point Dangci) whiie the coionv wls when the coiony is complcteiyoccupied, lead k) nestjng growing (Norman 2001). Prospectiveand new breeding (Norman at other local sites 2001).Further, although thcrc srtesare otten initrated by young bircis,particuiarly as hasbeen a low levelof interchangebetween locai colonies, populationsare expandinu (e.g. Nelson l98i). with threebirds from WedgeLight (PortPhillip Bay) being found at LawrenceRocks. there is no evidencethat any Recoveriesof gannetshave been made weli away from substantialimmigration from other siteshas supported thc LawrenceRocks, with birdstending to movewestward into colony expansionthere. Simiiarly, at Port Phillip Bay areasoff South Australia and WesternAustralia (and in one coloniesthe intrusionof birds from LawrenceRocks has caseto Mauritius);few have occurredto the eastof Port involvedabout 0.1 per cent of chicks bandedthere; while Philip Bay or Tasmania.ln contrast,the smallernumber 29 March,2004 F. l. Noman and C. Cooper AusltalianGannets at Lawrence Rocks

to, and occupied of recoveriesfrom Port Phillip Bay sites (also often shortly Australia) and were subsequentlyattracted gannets.Certainly after fledging) have occurred in a more restricted area breeding sites within, colonies of Cape sites have although in a usually western direction as far as Kangaroo Australasian gannet populations and breeding which Islandin SouthAustralia (Norman 2001) To someextent, increasedsubstantially in recentyears. an expansion for young banded at Lawrence Rocks, the distancato hasresulted rn complereoccupation of mostprevious sites recovery site decreasedwith age post banding: recoveries and the development of others, often with younger aged (Norman ol lhose of breedingage were more numerousin the birds from a presumedpool of potential breeders breedingperiod. The breedingstatus of recoverieswas, et el. 19981Norman2001; Bunce et a\.2002). and non- however,unknown and may include both breeders This study has shown that gannets from the Lawrence dispersaltends to be within the breeders.Nevertheless, Rocks colony disperse extensively into the coastal waters the pilchard,a prey specieswhose range itself is rangeof off South Australia and WesternAustralia for considerable isohyet(e.g. Kailola et al. within the 9 21"C sea surface periods, particularly when young and not breeding. 1993). Conservationof this population th€refore depends,at least Wingham (1985) consideredthat while the gannets' during non-breedingperiods, on activitiesand processes foraging range in the breeding period may extend to about beyondsingle state-basedfauna authorities.Management 270 kilometres,most occurredwithin 60 kilometresof the of the species and its required resourcestherefore should colony. However, Bunce (2001) found that average take accountof variationsin temporaldistributions. foraging distanceswhile adults were incubating were about 150 kilometreswhereas those during chick rearing were ACKNOWLEDGMENTS about 90 kilometres: throughout the breeding period We are indebled !o those involved in early banding at Lawrence foraging trips averagedabout 100 kilometres but were quite Rocks (G. Bowker, L. Burgess. R. Edge, J. McKean, L. O'Connor. T variable. Recoveriesin this study during the nominal Pescolt,J. Whcelcr and their assislanls) who provided a background for breedingperiod (September-February)ranged widely, but later activilies. In the laler banding sessions,inilialed by Elspeth were lessextensive than thoseoutside it. At this time too, Wiogham, several former Fisheries and Wildlife Ofiicers werc involvedi gralelul Peter Heylen, Ian populations. we are most io AIex Godfrey-Smith. there is some admixtureof birds t'rom other Weslhome and Ron Wollcrman for their reSular assistanceand interest Although most recoveriesof New Zealandbanded gannets We arc also most grateful to the ABBBS for their conlinuedhelp aDd occur along the easterncoast of Australia,some birds do supporl in providing copiesof onginal recordsor elcctronicfiles, and disperseto WesternAustralia and interveningwaters. Young in assistingin lhe resolutionof queries.Mrchael Scroggie (Arlhur Rylah Itom LawrenceRocks also appearto dispersewestwards, Insritute for Dnvironmental Research) kindly developed Figure I for us and Phillip Du Guesciin(Deparlmcnl of Primary IDdustry)allowed us oiien to WesternAustralian waters but those from Port acc€ssto lhe field noiebooks of Cracie Bowker, a vicwing $'hich Phillip Bay have (to date) not shown such extensive assistcdin rcsol!ing some issuesrelaling !o early banding.Iranej Sklra movements,being made mainly near banding sitesol in (Departmentof Suslainabilityand Environment,Waler and Environmenl, South Australian waters.Recoveries of birds bandedin in Hobar!) kindly provided a copy of thc Forvler and Servenly repon would EnvironDlent Australia for the provision of a Tasmania also indicate some movement to southern C C like 1() thank grant towards the cost of this study. Transporl to aDd from Lawrence Australia and, inirequently, Western Australia (see Rocks was providcd by former Fisheries and Wildlife Officers, Wodzicki I967; Marchantand Higgins 1990;Norman 2001 particularly the late Bob Jackson. To all, we afe grarcful, as we are lo for furtherdelails). Furlher, mo\emenl o\er ex(ensive Ashley Bunce (School of Ecology and Environment, Deakin University). distancescan be apparentlyrapid (e.g. more than 8 000 Dave Forsyrh (Department of Sustainrbilily and Environment)and anonymous relerees who commenled on an earlier draft. km in less than 30 days) but is substantiallyless than predicted from body mass and wing structure (see Pennycuik1997). REFERENCES (185E). The Cape gannet has now invaded two colonies in Bonwick,J. WeslernViclorja: its geography,geology, and social condition. (Brown: Geelong.) Victoria,those dt WedgeLight (1981)and Lawrence Rocks Buncc, A. (2001). Prey consumplionof Australasiangannets (Morrr (1993), and bred successfullyeither with anotherCape rerralor) breeditB in Pori Phillip Bay, soulheast Aus|ralia, and gannet(Lawrence Rocks) or with the Australasiangannet polenlraloverlap with commercial fisheries./CES J. Mdt S.i. 58i (WedgeLight, Venn 19821Norman e/ al. 1998;this study). 901-915. tsunce,A., Norman, F. L, Brothers, N. and Gales, R. (2002). Long'lerm This specieshas also beenseen or recordedoffshore (e.g. changes in the Australasian gannet (Mrlrr r?/roror) population in Ross 1988). However, at about the same time the Australia: the effecl of climate change and commercial fisheries. ,lrdr Ausfalasiangannet has expanded its breedingdistribution. Bid. l1lt 263-269. Lequette et c/. (1995), for example, reported on the Coutin, P (ed.) (2000).Port Phillip Bay fin fisheries- 1998.Fisheries Victoria Assessment Report No. 22. breedingof Australasiangannets (and the presenceof Cape Dycr, B. M., Upfold. L., Kant, W and Ward, V. L. (2001). BreediDg gannets)at Saint Paul Island (38'43'5,77'30'E)in rhe by and additional records of Australasian g r.net. ll,lotus seffator, in southernlndian Ocean,well outside previouslyaccepted SourhAfrica. O.\triclt7t ll4-126. breeding ranges.Two gannetswere first seenthere in early Fisher, J. T. and Cooper. C. (n.d.). Thc Ausrralasian galnleI. Motru! population 198?,although their breedingstatus was not determined. r..].drol, a study at Ilwrence Rocks S[ate Faunal Reserve, Portland. Departmenl of Australasiangannets Conservationand Nalural Resources,Porlland. have also been recordedat Crozet and Fowler, S. and Scrventy,D. L. (n.d.). A censusof rhe ganner,Srld Marion Islands,in South African waters(see Lequette er serrator, in Australia. (Unpublished reporr, copy held by th€ a/. t995 for details)and wirhin SouthAfrican colonies te.g. Dcpartment of Primary Industries, Water and Environmen.: Trsmania.) Dyer et al.200l). Perhaps,as with the recoverymade in Gaughan, D. J. (2002). Disease,rranslocationacross geographic boundaries must be recognised Mauritius, some young gannets as a risk even in the absence of dispene beyond normal disease identification: (he case with Australian Sdrdlnopr. Re!. Firl non-breedinghabitat (southemAustralia, including Westem Biol. Fish. llt tt3-t23. F !. Notman and C. Coopsr. AustralianGannols al Lawrence Rocks Corella28(l)

Gibbs, H. M.. Norman, F. l- and Ward, S. J. (2000). Reproductive Nelson,J. B. (1981).'Seabirds (:) tbeir biologyand ecology.' (Hamlyn: parameters,chick growth aod adult 'age' in Australasiangannets LoDdon.) Morussenator breedingin Port Phillip Bay,Victoria, in 1994-1995. Norrnan,F. L (2001).R€sights, recaptures and recoveri€s ofAusEalasian trnr 100: 175-186. g nnetsMorus sefiator breeding in Port Phillip Bay,yicloia. Corclla '17 Grant, J. (1803). 'The nanativeof a voyageof discovery.'(Military 25t -84. Library,Whitehall London.) Norman,F L and Menkhorst,P W (1995).Aspects of the breeding Hanis, M. P andNorman, F L (1981).Distribution and status of coastal alrdfeedrng ecology of theAustralasian gann€t Motus serrutor in Potr coloniesof seabirdsin Victoria.M€rn. Na' Mus. Vc. 42| 89-106. Phiuip Bay,victoria, 1988-92.Enu 95| 2340. Hawkins,J. M. (1988).The FarewellSpit gantretry- a trew sealevel Norman. F. L. Minton, C. D. T., Bunce,A. and Govanstone,A. P colony. Nolornrr Xst 249-260. (1998).Recent changes in the statusof Australasiangannets Morus Kailola, P J., Williams, M. J., Stewart.P C., Reicbelt,R. E-, McNee, serratorh victotia. Enu 9Et 147-150. A. and Grieve,C. (1993).'Australian fisheries resources.' (Bureau of Norrh,A. J. (1914).Nests and eggs of birdsfound breedingin Australia Resource Sciences and Fisheries Research and Development andTasmania. Special Calalogue No. 1, Ausfalian Museum. 'optimal' Corporation:Canbena.) Pennycuik,C. J. (199?).Actual and fli8ht speeds:field data Lequette,B., Berteaux,D. and Judas,J. (1995). Presenceand flrst reassessedJ. Exp. Biol.200t 2355-2361. breedinganempts of southemganD€ts Mor{r capensi[ ar.dM. setrctor Pescot!.T. W (1980).Seabird Islands no. 100Lawrenc€ Rocks, Victoria. at SaintPaul Island. southem Indian Ocean. Enu 95: 13+13'l. Corella4: t0'/-109. 'The Marchant,S. and Higgirs, P (eds)(1990). handbookof Australian, Ross,G. J. B. (1988).Caplure of a ringedCape Bal'retSula capensis New Zealandand Antarcticbirds.' Vol. l. (Oxford UniversityPress: ofr Australia.Cornorant 14. 3-19. Mclboume.) Venn,D. R. (1982).The Capegannet (S!la cdp€nsir),a new recordfor tvla$ingley,A. H. E. (1908).A night with the birdsof LawrenceRocks. Auslralia.l4c. lvdr 99: 56-58. 14..Nat. 2St 12-24. waghorn,E. J. (1983).Population changes of the Australasiangannet Mattingley.A. H. E. (1934).Notes on the polentialitiesof guaro Mo.us serrator (Gray) at the Mota Karamaramagantrery, Hauraki Droductionin Australia.tm! 331236-241. Culf. New Zealand.Emu E2. 286-295. M;Keatr, J. L. (1966).Population status and migrationof the gannet Wingham,E. J. (1985). Food and feeding range of the Australasian Suh bassanaserrator of LawrenceRocks. Enu 65: 159-163. Neira, F., Coutin, P, Morison,A. and Hall, K. (eds)(1997)- Pilchard wodzicki, K. (1967).The gannetsat CapeKidnappers. 2. Dispersaland - 1996.Fisheries Victoria Assessment Report No. 13. movements-Trans. Roy. Soc- New zealand9t l'7-31 Nelson,J. B. (19?8).'The Sulidae(i) gannetsand boobies.'(T.and A. D. Poyser:Berkhamsted (U.K.).)