From Field and Study: Distinctive feeding behaviour of Red-necked Avocet at Augusta, Western Australia

2010·0.79 MB·English

by  Joseph Froudist

FROM FIELD AND STUDY
Distinctive feeding behaviour of a flock size of 250 individuals,
Red-necked Avocet at Augusta, which was by far the largest flock
Western Australia - The Red¬ I have ever seen in the south¬
necked Avocet (Recurvirostris west. On occasion, the flock
novaehollandiae) is a tall long- would split into either two or
legged common nomadic three sub-flocks, which would
shorebird found in suitable end up in different parts of the
wetlands throughout mainland estuary near the river mouth, at a
Australia, and as a vagrant in distance from each other of no
more than about 200 metres. 1
Tasmania (Slater et al. 2004).
observed a very striking
Simpson and Day (2004) list
phenomenon, when, on four
preferred habitat as tidal flats,
occasions over a three day period,
marshes, saltworks, and shallow
I saw one of the sub-flocks take
inland salt lakes. These birds are
to the air from where they were
usually found in pairs or small
foraging, and begin to fly up and
flocks, and feed by swinging the
down above their feeding site.
bill from side to side while
Immediately this occurred, the
wading, or tip-tilting while
other sub-flock or sub-flocks
swimming (Slater et al. 2004).
would lift up from where they
They have partly webbed feet,
were foraging, and fly swiftly to
and are often found swimming.
where the group was lifting up
They are predominantly white,
and down, and the entire group
with a chestnut head, a long
would then settle down to feed.
black upturned bill, a black wing
As Simpson and Day (2004) have
bar and wing tips, and dark
stated, the birds in flight were
stripes down the side of the back,
very distinctive, and to me the
described by Simpson and Day
different markings on the body
(2004) as being “distinctive in
and wings as the birds moved up
flight”. This fits with my
and down created a spectacular
observations as described below.
“flashing” effect, which could
In 2005, I was staying at Augusta
easily be seen from quite a
in the far south-west of Western distance away. It seems as if this
Australia, and had occasion to behaviour provided a signal to
visit the large sand-bar at the the others that there was good
mouth of the Blackwood River, foraging at that site. Certainly,
which is adjacent to the town. I the immediate response of the
observed an unusually large flock other group/s as described above
of Red-necked Avocets feeding in would imply that this might be
the shallows near the river- so. This was the only period
mouth. Over a period of three during which I have observed
successive days, I made estimates this type of behaviour, and I have
of the flock size on a total of more not come across any reference to
than ten occasions, and settled on this in the literature.
182
REFERENCES Although I could not see the
Dugite’s head, it was obviously
SIMPSON, K. and DAY, N. 2004.
aware of me as it began to
Field Guide to the Birds of Australia
disappear a few seconds after 1
7th Edition. Penguin Group,
stopped to observe it. It took
Australia.
refuge amongst the surrounding
SLATER, P., SLATER, P. and
tangle of vegetation and the low,
SLATER, R. 2004. The Slater Field dense skirt of the Xanthorrhoea:
Guide to Australian Birds. Reed New indeed, although I could not see
Holland.
for certain, I gained the
- JOSEPH FROUDIST, 17 Tabard impression it may have moved up
St., Greenwood, Western Australia into the Xanthorrhoea skirt. While
not as quick to escape as a Dugite
disturbed during the warmer
months, it was nevertheless quite
Winter activity in the Dugite,
sure in its movements and had
Pseudonaja affinis - Of the two
disappeared from sight after
most commonly encountered
several seconds. Although the
large venomous snakes in the
day was cool and cloudy with
Perth metropolitan area, the
occasional patches of sunshine,
Dugite Pseudonaja affinis and the
the Dugite’s dorsal colouration, a
Tiger Snake Notechis scutatus, it is
dark monotone brown, would
generally accepted that Tiger
have helped it to absorb heat. The
Snakes are cold tolerant and may
temperature range for the day was
be active during winter, whereas
7-16W! (Bureau of Meteorology).
Dugites prefer warmer conditions
and remain inactive throughout
the colder months (Softly and REFERENCES
Cockett 1967; Storr 1988; Bush et
BUSH, B., MARYAN, B., BROWNE-
al. 2007). However, on 21 June
COOPER, R. and ROBINSON, D.
2009 at about 1.15pm I observed a
2007. Reptiles and frogs in the bush:
large (>lm total length) adult
southwestern Australia. University
Dugite basking in Star Swamp
of Western Australia Press,
Bushland Reserve (31°51'S,
Crawley.
115°46'E).
SOFTLY, A. and COCKETT, E.G.
The Dugite was coiled at the base
1967. The overwintering of some
of a Xanthorrhoea preissii, located
captive indigenous reptiles in
immediately adjacent to a
Perth. Western Australian Naturalist
limestone track in an area of
10:100.
Tuart open woodland. Its coils
STORR, G.M. 1988. Dangerous snakes
were arranged laterally but
of Western Australia (rev. ed.).
resting on the side of the
Western Australian Museum,
Xanthorrhoea trunk and therefore
Perth.
perpendicular to the ground -
presumably the better to absorb - PAUL ORANGE, 18 Balfern
heat from the low, weak sunlight. Court, Hamersley, WA 6022
183