September,1978 Declineof the Gannetryon Cat lsland,

.IOHNWARHAM & D. 1,.SERVENTY

Cat lsland, Tasmania, is one of the lew breeding places within of the AustralianGannet Motus setratot. It is ihe most accessibleof the gannelriesand has been the focus ol attenliontor many visitors since Flindersfirst surveyedthe in the area. Apparentlythe gannetry was discoveredby Flinders but he made only incidental mention of it is his book (1814.p. cxii).He statedthat on B January1799'Mr. Bass went on shore 1o lhe small,south-eastern islel l-Cat lslandlwhence he broughta boat load of seals and gannets.' The lollowing summary of the gannelry's history comes partly lrom an unpubljshed review of Australlan gannetrles (by D.L.S.) and partly lrom the liles of the Tasmanian NationalParks and WildlifeService.

On 20 ancl2l Novclrber. ltl93. whcn a party Tasmlnian Fauna Board (now thc Tasnanian llonr thc ViclorianFicld Nuturalists'CIublandcd, National Parks and Wildlifc Scrvicc) filcs thcrc thcrc \\crc e\tinlirtcd 10 bc bctwcsn 2 4(X) and had bccn .1500-5 0(X) arlult birds ashorc cilrlicr I 600 birds on ncsts, thc rookery bcing circular, that ycar. lTo detcr lurther raids a wardcn, of about 50nr dianrcter (Cabricl, 1894) and W. A. Riddlc. was stltioncd on nclrby Babel 150nr cilcLrnrfcrcncc(('rnpbcll, 1894). D. Le Islandduring partsof thc 1935/36 and 1936/37 Soucf lirndccllo\\'ilrds thc cnd of November, I 901, brccdingscasons. On lll Junuary, 1937, about and founrl onl;-- frcsh cggs present (I-c Soucf, 5(X) chicks wcrc bcing ririscd arrd {i00-900 thc 1902). No cstimrtc ()f tlrc nunrbcrswas givcrr bu1 oo ll Novcnrbcr. 1907, thc nestscovered ('hicks (Atkinson l9l2), and Nlonth/Yeirr Adulls about 0..+h in North, or Scrson nruch thc sirnrcotrtaincd on .1 Dcccmber, l90ll, ( Whirc. I 909 ). Whitc describccl the rrival of lt/ 1893 2 400-2600 the AustrrlasianOrnitltologists' Unien party at I I / t90ri 5 000-10(x)0 'What thc gaonelr)- as follows: a marvellous tt/1912 3 000 l0/ t 9:15", 800-t000 sight rnct our eycs!On this barc crcst of thc | / t93'l i 2 000 500 wlrs r Ganncl (Sulq \ututor) rookcry, ln acrc 1937/3u i I100 li(x)-900 ' "a ol living ncsting [rirtls. e'ach sitting on a littlc 193{3,',39 conpleof lhouslnd' t{){)0 nound of carth and rl:bri,r, with a slight 3,rt94l 100-150 rriscd t2/ 1911 Numbersvety low, tleprcssionon thc top, ilr which rcsted a single 4/ 1945 t4 clirty-whitc cgu. Flch bird rvas just out of rnngc t2l 1945 900 ,{50 of its ncighbour'sbill.' I191',7 19,17,llt ,100 19.19',50 ,100-500 1t5 (?) .,\nothcr nrcmber ol lhc piLrty, W. N. Atkins t950,5r 200 ( 1909) cstimllc(l th t 5 000-7(XX) birds were t95I 5l 150 4u nc\ting.und anotherestinratc fron thc samc l9Jl,'5,1 100 Nil )cl r954155 t 114 43 visit $as bctwccn 3(XX) anrl l0(XX) gnnncts 140 45 lrrecding ( Mcllor in Mathcws, | 9 l4 ) . By latc ti6 t4 Novcnrtrcr.1912. the nunrb!-rswcrc said to havc 1957/5lJ l6 W. Fini- t951359 6o ll clroppcrl{Mcllor and Whitc, 1913) and 42 t1 gan (Chisholnr. I959) rccordcd about 3000. This trcnd sccnls to hilve continucd, ls on 23 l!167.611 21 Octobcr. 1935,lt00-1000 birds were nestingon 19(18/69 ?6 '75 'an (0.4 (Anderson t9'74/',75 1',7 ,7 wc'll undcr acre' ha) and 1975/',76 17 Anrlcrson. I936) with bare arcas around the 1 197'l 14 6 colon!". lt \!ils stirted that somc lishcrmen had ' *': becn taking thc birds for bait and rccording to i + Refel lo tc\1 J. Warham & D. L. Setvenly:Cat lsland Gannetry Cotella 2 14)

lirllowins season.A hut was built on Cat Island in 1977, therc wcre l4 ldults and 4 lar!{c, I tlrc summcr of 1937/38; F. Nillson was stationed mediun)-siz!'dand I srrrallchick. thcrc that scason '['hcsc and W. A. Riddle ln 1938/39 ligurcs show au appalling dcclcasc in aftcr which guarding ccascd. the 70 years sincc Whitc's visit in 1908 (White, loc, dt.), nostiy duc to prcdationand vandalism (ln 2(r Novcnrbcr, [938, one of us (D.L.S.) by lishermcn nd othcrs. Thc following tablc landcd on Cat Island from M.V. Warreen and clearly shows this declinc. nradc a brief survey o[ the birds present.A small suurplc of the gannct ncsts was counted and it Numerous photographs of thc gannctry have wls cstimatcdthitt thcrc was a tol l of 750-l 000 appearcd,the first by Gabricl (1894'), others b1 ncsts containing eggs tnd young in white down. Campbell( l90l ), Lemprierc(in White, 1909), Horvcvcr. thc warden (Riddlc) said that there North ( l9l2), Barrctt( 1919),Cashion (l95ti) \\crc a'couplc of thousand'gannets present. At irnd Servcnty?t al. (1971). Lc Soucf (1902) thc tinlc of observationhc said that only a part rcported a solitary gannctsitting on its cgg among of thc birds wcrc ashorc but that thcy arrivcd thc cormorants on ncarby Storchousclsland in fronr thc fcedinggrounds at I I a.rn.and rcmained latc Novcmbcr, 1901. Rcscarch on grnncls in until .1 p.m. An aerial survey by S. Fowler a tcw 1957/-58 concentratedon bchaviour (Wrrh u), dals carlicr (23 Novcnrbcrat ll a.nr.)gavc I 02lt 1958). ne\t\-thc mean of two counts. Acknowledgemenls Dr l. Eberhard nd Mr Nigcl Brothcrs pro- Fcw data arc available lrom thc pcriod of 'lasmanian vidcd data from thc National Parks World War lI except that about 100-150 ganncts and Wildlifc Scrvicc'slilcs to updatc the history. wcre seen on 6 March, 1943. But reports fron L)ecenber, l9zl4 show that the numbers were vcry low, rvith only about 1.1 birds on References voung 'The 17 April. Aerial studieswere madc by S. Fowler Anderson,B. xnd G. M. Anderson(1936), Crt in 19,15and 1946 but no young wcre identificd lslandCirrnet Rookery', trr& 35: 333-334. Alkins,W. N. (1909), Noteson a lrip to the Stnrils olthough up to 900 rdults werc around on l8 lslirnds, ?./rrrdlridr Nat. li 10-12. Dccernbcr, 19.15.On 23 March, 19217,a landine llurrelt, C. (1919), ln Australiirn wilds: lbe gleanings was nradcand sonlc 450 adult glnnets wcre seen: of il naturalisl.Melbourne Publishing Co., Melbourne. Crmpbell, A. J. (1894), 'Rcport of expedilir)nto Fl|r- they seemeddisoricntilted and weak and'stumbled neaux Croup', ViLtoriun Nat. l0: 179-183. around' irs thc pxrty approilchcd. ln 1947/.+tt Crmpbell,A. J. (1901),Nests and Eggsof Australian ,+00adults wcre secn; in 1949/50 400-500 adults Birds. irrcthought to havcraised I35 young:in 1950/5| Cushir.n,T. (1958), fhe birds of Crl lsland,Furnerux Cnrup. I irsm.rniir'.Lrl// 5b: ll7_111. thcrc were 55 young,rnd in l9-5I/52 150 adults Chi\lrohD,A. H. (1959), Cannets of Cirt lsland', wcrc countcd and 48 young raised. In the ncxt Victt)tiut Nut. 75: 188-192. scusonabout 100 adults werc seen but no young Flinders,M. (lltl,l), A Voy.rge1()'ltrrr Auslrnlis. Gabricl, J. (1894), Reporl ol expedilionlo Furneaux relred.Then in 1954/55 ll4 adultswcrc prescnt (lr,rtrp,/nr,fnrlr N.r/. IU: lh7-la,ll. and 43 young raiscd+. this being the nrst post- l-e Souef, D. (1902), A visil to lhc war scasondurin-q which a wardcn (A. D. Har- of IslAnds',Victuria Nal. lu: l8l-188. krnd) was ashorefor at lcast part of thc brceding Mathe$5,Ci. M. (I914), The birdsof Ausl.alit.4: 19. Mellor,J. W. rnd S. A. Whire (1913), Flinderslshnd pcriod. [n thc iollowing ycar up to 140 adults Clanlp-oul',EDtu l2t 158-164. raised 45 young. In 1956/57 14 chicks fledged, North. A. J. (1912), Nests and Eggs of Birds found and in 1957/58 l6 chicks were presentwith the breetiingin Auslralia,vol 3. Auslralian Museum. (1971). ashore that season Servenry,l). I-.. V. N. Serventyand J. Warhan nraximun count of adults Thc Handbook of Australian Ser-birds.A. H. and being67 on 4 December,1957. In 1958/59 60 A. W. Reed,Sydney. rdults and l3 chicks were seen; in 1959/60 wrrh nr. J. (1958), The nesting of the Auslralian thcrc wcrc 42 adults and .17 chicks. 1'+Wardens Gannet',trrtl 58: 339-i69. Whire, S. A. (1909), Narrxtive of the E\pedition pro- wcre no longcr prcscnt after 196O and counting moled by tbe Austr lasian C)rnilhologisls'Union1() lapscduntil 1967,r68whcn 22 adults and 9 chicks lhe islandsof BassStrait, Emu E. 195-207. wcrc sccn. ln 1968/69 26 udults wsrc countcd with 5 chicks: in 1974/75 l7 adults and 7 chicks John Warham, Zoology Department, University ol were prcscnt in Dcccnlber:in 1975/'/6 l2 adults Canterbury.Chfistchurch, New Zealand. and 7 chicks were rccorded,and on I I February, D. L. Serventy,2TEveretl Street, Nedlands, W.A.6009.