Con,
ALL members of the Anatidae (ducks, swans, geese etc) as well as all members of
the Rallidae (rails, coots etc) all undergo a complete moult of their flight
feathers in one go. There may be other families that also do this that I am
unaware of. Usually ducks will find a densely vegetated swamp to undertake
their moult, such as your Pacific Black Duck, or in the case of say the
Australian Shelduck (aka Mountain Duck), they will find a large open lake, such
as, when they are full of water, Lakes George and Bathurst. This is so that
they can either hide in the reeds or see potential threats coming and can dive
underwater.
One of the problems with this strategy for the birds, at least in those
Australian states that still have duck shooting (I refuse to use the term "duck
hunting") as was shown when I was working on waterfowl at CSIRO under the late
Dr Wayne Braithwaite, is that this moulting time occurred during duck shooting
open seasons - the birds really were "sitting ducks". Despite these findings,
the shooting lobby still persuaded the relevant governments to go ahead with
the shooting season anyway.
The research showed that the birds moulted from about now into late March.
Given what is happening to the climate and rainfall now it is ludicrous for
those states that still permit the practice to allow the shooting to go ahead.
Mark
-----Original Message-----
From: Con Boekel
Sent: Sunday, 7 February 2016 6:18 PM
To: canberrabirds chatline
Subject: Further to the moulting Black Duck
Earlier today I posted an image of a Black Duck which appeared to be regrowing
feathers after moulting - probably primary and secondary wing feathers. The
image attached is of a bird that was hanging around with the moulting duck. It
too appears to be heavily into moult. The size of the wing seems to me to
indicate that this particular individual is flightless. I don't really know
whether that is correct, or not.
I have heard of some species moulting all their feathers at once and being
flightless while doing so but I must admit it had never occurred to me that
Black Ducks might spend part of their year being unable to fly.
regards
Con
Black Duck
JWNR
7 February 2016
Con Boekel.
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