J4 Corella 5 (2) Noteson the Nestand Eggsof the Australasian Grebein north-westernVictoria PETER DANN

A description of the nests and eggs of AustralasianGrebes is given. based on a sample of 70 nests recorded in WyperfeldNational Park, north-westernV-ictoria. The results are compared with published data on the breeding ot the Little Grebe in Europe.

There is little published information on the branches,twigs and leaves anchorcd to partially breeding biology of the Australasian Grebe submerged vegetation. The greater part of the Tachltbaptus novaehollandiae. Tarr (1971 ) re- nest structure was submerged. The eggs were corded the Australasian Grebe in Wyperfeld placed in a "numerous central depressionin the top of the National Park as in Black Flat in nest, often with the lower side of the egg in 1957", but made no other mention of its occur- contact with the water. The water within the rence there. In late December 1975 the lake central egg depressionof the nest felt noticeably system in the Park filled for the first time since warmer than the temperature of the water sur- 1957. In 1976 large numbers of Australasian rounding the nest. The averagedepth ol a nest Grebes nested at Black Flat in the Park, and rvas approximately 3-5 cm and the average nest oll some smaller lakes further upstream. These rviclthwas approximately 33 cm. A summary of lakes filled when the floodwaters from the Wim- the dimensions of six nests is presented in mera River reached Outlet Creek and flowed Table l. through the Park connectinga seriesof swamps and lakes. This paper reports data collected on Nest nuterial nests and e-sgsat Black Flat (30' 32'S., l4l" Coarse material, such as twigs and small 58'E.) in February 1976. branches,was placed towards the bottom of the nest, and leaves, grass stems and rvaterweed Methods conrprised the upper section of the nest. The main sourceof nest material was River Red Gurn _ Scventy nests were located in the vicinity of E ucolypl us canal duI en.si.s. Black Flat between 7-11 February 1976. Eggs were counted, measured to the nearest 0. I mnr Nest site with vernier calipers,and weighed to the nearest The nesting platforrn was moored to vegeta- O.-5g with a Pesola 5O g spring balance. All tion either by protruding nest tnaterial, parri- visits to nests were made by canoe. Nest dinen- cularly at the base of the nest, or by the incor- sions and water depth were measured using a poration of the anchoringvegetation into the nest paddle marked with 25 cm graduations.Estimates of the distancesof nests from land were made relative to the length of the canoe (2.5 m). TABLE I Additional data on clutch size were obtained from the RAOU Nest Record Scheme. In the Thc approximate dimensions of six ncsts of tlre nest record cards, clutch size was determined AustralasianGrebe at W_vperfeld. orly from nests whose number of eggs did not Nest change between two consecutivevisits, at least measuremenl Range (cm) 48 hours apart. Diameter above $ater 15-25 submerged 25-40 Depth above watcr l-6 Results submerged 20-35 Nest structure lncubation Depression diameter 4-7 The nest was a floating platform of small depth 3-6 June.198.1 P. Dann: Nest and Eggs of Australasian Grebe

TABLE 2 TABLE 3 Nest anchorages of the Australasian Crebe at \\';;perfeld. A comparison between the number of eggs found in nests at W,vperfeld and the clutch size as- determined flpe of anchorages Number Percentage from RAOU Nest Record Scheme data. Sapling " l0 l8 Number (dead) l5 27 of eggs in clutch Hanging branch 123456789 TOTAL " t0 l8 (dead) t1 26 Number of clutches 'fotalFallen tree 6 ll (total) 5il6107100040 55 r00 Number {containing onll brown eggs) 0 52 841000 20 Number (nest

record scheme) 0 2 3 7 912 6 1 | tt stnrcture. -IableThe types of nest anchorageusecl are shown in 2. Of -55nests, 5 | wire situatecl within the floodedtree-line arountl the 'andperimeter of three lakes (irrcludingBlack Flat) four Discussion rvere located in a slow-flowing stretch of creek. The breeding Long strctchesof faster flowing creek with appar_ of the Australasian Grebe in large numbers in park entlv suitableanchorages available were not uied. Wyperfeld National soon after the first The mean water depth at -55 nest sites rvas floodwaters appeared-breeding demonstrates an ability 1.3 m (s.d. r- 0.45 m) with a rangeof 0.5-2.5 to use ternporary conditions at short notice within m. The mean distance from lancl was 39.3 m the breedins ieason. The -r carliest. breeding pair (s.d. 30.2 m) with a ranse of 10-150 m. found begln eggJaying approximately Water dcpths up ro 3.3 m wire availablebur two weeks after the floo-dwaters reached the the water depth within the flooded tree-line Park. However, since 4OVo of the clid nests not exceed2.5 m. being used. contained newly laid eggs in early February..rhe majority of ihe popul*ation Degan.nestrng tn Description ol tlte egg late January. The timing of breeding is consistentwith Newly.laid eggs are pale bluish-white thit r:iven bv Siorer .. with a (In_ReadersDigest, ..m6stly tuny coatlngt a brown stain 1976) as September develops as incuba_ to January". -l-heti_on proceeds (Serventy and Whittell, 1965). dimensions (mean- -+- s.d.) of l l -5 eggs It was thought that nestscoutaining onlv brown were 36.52 -+ mm 1.22 mm x 25.17 nlir eggscould be used to estimateclutc-h size as the - 0.63 (ranges rnnr 33.2-39.4 mm and 23.7_ absence.of white (newty-laid) eggs suggested 16.(r rnm). The weight"0.85'i (mean +- s.d.) of ll-5 that had finished.A cornpariio-n was r- .j.ilri.s -laying of ciitches 9;fgs 123 g tr""g. gt. of all brown e-egsand clutch sizesobtained from hts ls no.t representativeof ,t the rveightof newiy the nest record scheme (Table 3 ) indicates laid eggs because of the weight loss*that occurs differences in both the mean values and ranges during incubation. of the two samples.Complete clutchesfrom ihe nest record scheme ranged from 2_9 (-lutc'h and the size most frequently recorded clutch was six eggs. ( , . . The number of eggsin all clutches,the number lutches containing_only brown eggs at Wyp'Jr_ ()l eggs in nests with only brown eggs, and thc tetd ranged from l-6 and the rnbst frequently nuurber of eggs in 4l clurchesobtaiiJspecies. 4-10 F tcmDeraturedifference between the nest and thc water in which it la1'. Although the temperaturedifference was not nreasuredat Black Acknowledgemcnts Flat, it was apparcnt that the water in the egg I should like to thank Peter Menkl.rorstand chamber was considerablywarmer than the water Peter Trusler who assistcdin the field arrd the surroundingthe nest. Whether this was due to Victoriar.rNational Parks Service for permission the reccntDresence of the incubatinebird or was to carry out the study in Wyperfeld National a proclr,rct6f decompositionof the p"lantmaterial Park. I thank Helen Young and the various in the nest is not known. but warrants further contributorsto the RAOU Nest Record Scheme study. for use of the clutch size infornlation. I am grateful to Jane Bird for typirrg the manuscript The AustralasianGrebe and the Little Grebe irnd to Dr Angus Martir.r for nraking helpful Tacht'ltuptus rttficollis are thought to form a suggestionsin the preparationof the manuscript. superspecies(Cranrp and Simmons. 1977). The nest structureof the Little Grebe in Europe is sirlilar to that of the AustralasianGrebe. The References nest dianleter at the basewas up to 60 cnl wide; Cramp, S. and K. E. L. Simmons (eds.), (1977)' The thc averagediirmeter of the nest cup (incubation Birds of thc Western Palcarctic, Vol. I ', Oxford clepression) rvas four centimetersand the height Universitl' Press, Oxford. ol the nest above water was four to live centi- Reader's Digest, (1976), Complete Book of Ar-rstralian Sen'ices, Sydne-v-. flretrcs(Cranp and Simmons,1977). These are Birds, Reader's Digest (1976),-Birds of l. In Europe,the Serventy, D. L. and H. M. whittell, similar to the valuesin Table Western Australia (5th Ed. ), Universit-v..of Wcstern mean dirnensionsof 100 e-ugsof the Little Grebe Ar.rstralia Press, Perth wcre 26 mnl x 38 mm with rangesof 24-28 rnm Tarr, H. E. ( t 97 1) , The Birds of \i l perfeld Nat ional and 33-44 rnm respectively.The mean egg weight Park, Panrplrlet published for the National Parks was l4 g (presumablyat laying). Clutch size Service of Victoria. is given as four to six, ranging from two to (Cramp and seven with up to ten recorded P. Dann.Department of Zoology. Simnrons, 1917) . Thus, egg wei-ehtsand clutch Universityof Melbourne. sizes of the Little Grebe and the Australasian Parkville.Victoria, 3052.

Auxiliary at the Nest of the Blue-faced Honeyeater

Dorv ( 1980, Enru 80: 121-140) listedsixty- faced individualwas sittingorr the nestwhile thc fivc speciesof Australian birds for which com- other two birds brought food to the young. The nrunal breeclinghad been recordecl.He mentioned voung were fed about once a minute. Alexander severalothers that may be possiblecommunal i tgl-6. Aust. Bird Bander | 4: -52-53 ) noted breeclcrs. Although he cited reports of Blue- from banding studies that the facial patch re- faced HcrneyeatersEntont)'7.ott cyattotis exhibit- tained the olive-green colour for at least six inc this behavior"rrin aviaries.he had no similar months before obtairring the blue of the adult. rcl'tortsfor uild birds. We assume that the bird rvith the olive-green the offspring of the primary pair (the On I -5th October 1979. we observed this patch was pair) and hencesatisfies Dow's clefini- speciesnesting one kilometre east of Weethalle, blue-faced an auxiliarv. N.S.W. (33 5'S., 146'37'E.). The birds were tion of observed in attendance at the nest which was about 4.-5rn from the grourrdin the outer canopy WalterE. Boles,N. W. Longmoreand T. R. Lindsey of a lorv cucalypt.Two had blue facial patches, Department of o rnith o rost, t n"rf,X:'li the othcr. irn olive-greenfacial patch. One blue li3.$l.r.,ji :