Table Of ContentDESCRIPTION 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
