DESCRIPTION OF AN IMMATURE MALE KERGUELEN PINTAIL ANAS EATONI COLLECTED AT MAWSON STATION, EASTERN ANTARCTICA By R.EJOHNSTONE Department of Ornithology, Western Australian Museum, Francis St, Perth, Western Australia 6000, Australia and L.G. IRVINE Australian Antarctic Division, Channel Highway, Kingston, Tasmania 7050, Australia INTRODUCTION immature in post juvenile moult, a plumage stage apparently so far On 6 December 2001, an undescribed. Accordingly, a full unidentified duck (Anatidae) was description of the specimen is sighted at Mawson Station detailed below: (67°35’S, 62tf52’E) in Eastern Total length 443 mm; weight 340 Antarctica. It was seen flying and g; entire culmen 45.0 mm; exposed walking around the Station culmen 35.0 mm; bill width 12.6 between 6 and 11 December, often mm; bill depth (from rear of feeding in puddles at the sea shore nostrils) 15.2 mm; wing 219 mm; (Figure l). The duck was not seen tail 93 mm; tarsus 33 mm; middle after 11 December 2001 and was toe and claw 48 mm. Skull fully found dead on 29 December 2001. ossified and testes 11.8 x 4.1 and 11.3 It is thought to have died during x 4.6 mm. a blizzard on 13 December. Forehead, crown and nape The duck was collected and blackish-brown (the feathers returned to Australia for positive edged with dull cinnamon brown). identification. The specimen was Lores, ear coverts, cheeks, sides of sent to the Western Australian face and neck paler, the feathers Museum where it was prepared variably edged dull buff (there is a into a study skin (registered richer tone on chin and cheeks number A34698) and identified as and greyer on foreneck), the an immature male Kerguelen feather centres (sometimes Pintail Anas eatoni. reduced to mere spots) dull brownish-grey, producing a freckled effect, heaviest and DESCRIPTION OF THE darkest on the ear coverts, but SPECIMEN barely visible on chin and throat. The bird appears to be an Hind neck blackish-brown, the 164 Figure 1. The Kerguelen Pintail feeding in snow-melt at Mawson Station, 9 December, 2001. Photographed by L. Irvine. 165 feathers with obscure warm towards tip); secondaries blackish- brown edging (the zone brown to blackish on the outer contrasting rather sharply with web, slightly glossed with dark sides of neck). Upper mantle olivey green (forming a dull mostly dark greyish or blackish- speculum) and fairly broadly brown mottled with dull white, tipped cinnamon buff shading to the feathers with pale greyish- white terminally, and greyish- brown or whitish concealed bases, brown on inner web (the outer grading darker brown distally and feathers with a whitish sub¬ with greyish-white tips; some terminal bar or mark, and white feathers on the sides of lower tips); tertials long and pointed, mantle vermiculated with dull black broadly edged with brown white or buffy white or with fine or brownish-grey and narrowly wavy whitish lines; also the pale margined with greyish-white. Tail fringes generally becoming (wedge shaped, the feathers broader on the lower mantle somewhat acutely pointed) giving an overall mottled mostly greyish-brown to dark appearance. brown the feathers with narrow Back mostly dark brown to dull white outer edges. blackish-brown, the feathers with Lower neck and upper breast concealed pale greyish-brown mostly dull buffy brown coarsely bases, darker distally and with mottled with dark brown bars two narrow irregular white or and buffy white. Lower breast and greyish-white bars and greyish belly dull buffy brown, the tips. Rump feathers mostly brown feathers with whitish concealed with whitish margins. Short bases, narrow brownish shaft scapulars mostly greyish-brown streak and some feathers with a basally and with blackish, dull greyish subterminal blotch (giving white and buffy white bars and a fairly mottled/spotted appear¬ vermiculations, the longer ance). Sides of breast and flanks pointed feathers with broad mostly dark brown with coarse blackish central streak grading to wavy whitish or buffy brown brown (sometimes mottled bars, occasional feathers have the darker) and edged with dull brown areas peppered/vermicu¬ white. lated with white and greyish Lesser upperwing coverts mostly white (giving a mottled brown, edged with brownish- appearance). white or greyish-white; greater Thighs barred with dull brown coverts mostly greyish-brown and brownish-white. Undertail with dull greyish-white tips that coverts mostly irregularly barred form a border to speculum. or marked with brown and dull Primaries and primary coverts cinnamon buff and edged white. mostly dark brown on outer webs Axillaries barred with dark brown and tips grading paler greyish- and white. Lesser underwing brown on inner webs and coverts mostly dark greyish- narrowly edged with greyish- brown with whitish tips; median white, shafts pale brown (darker coverts similar but with a whitish 166 subterminal bar and tip and only really visible on the greater coverts grey with a faint ‘shoulders’) and the short tarsus whitish subterminal bar and tip; we consider the bird to belong to undersurface of remiges brownish the nominate subspecies A. eatoni grey (paler overall tone than eatoni from lies Kerguelen. coverts), the secondaries tipped The Kerguelen Pintail is endemic white. Undertail similar to to the Kerguelen and Crozet primaries. Islands of the Indian Ocean, Bare parts (from photographs of where it is essentially sedentary live bird): iris dark brown; bill (Marchant and Higgins, 1990). The strongly patterned, upper bird collected at Mawson Station mandible sides bright blue or is thought to have been caught in bright bluish-grey with top of an intense weather system and culmen from forehead to tip transported 2000 km SSW, from (including nostrils) greyish-black the Kerguelen Islands to the forming a dark central zone, lower Antarctic coast (Irvine et. al. in mandible brownish grey with prep). what appears to be blackish tomia (cutting edges); legs and feet olive brown, webs dark grey. ACKNOWLEDGEMENTS This work was carried out with support from the Australian DISCUSSION National Antarctic Research Judging from plumage (especially Expeditions (A.N.A.R.E). We thank the relatively small and dull wing Steve Rendell and Dan speculum and traces of breeding Humphries (54,h A.N.A.R.E) for plumage on upperparts), size of locating the duck carcass. testes and date of collection (December), we believe this bird to be an immature. The aquisition of REFERENCE breeding plumage in adults occurs MARCHANT, S. and HIGGINS, P.J. from April to July and is complete 1990. Handbook of Australian, New by September. Also judging from Zealand and Antarctic birds. VoL l the plumage (limited extent or Ratites to Ducks. Melbourne, traces of vermiculated feathering Oxford University Press. 167