canberrabirds
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To: | "martin butterfield" <>, "David McDonald" <> |
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Subject: | Definition of DY in Aust Wood Ducks [SEC=UNCLASSIFIED] |
From: | "Whitworth, Benjamin - BRS" <> |
Date: | Wed, 23 Jan 2008 19:41:20 +1100 |
I have also been dealing with this issue this year, having
been watching ducks and swamphens etc more closely.
Perhaps with dy you have to take into account the 'degree'
of precociality of the species (if that is a word).
On a 'wikipedia' site they have precocial and
'superprecocial' heh heh.
Anyway, ducks are pretty precocial, they generally only
rely on their parents for a few days/to a few weeks for direct feeding
assistance, and often then the parents only give 'directions' so for black ducks
the parents give directions, some coots directly fed (passed food beak to
beak) their few-day-old chicks but even these chicks also fed themselves a
bit.
Swamphens seem to beak feed for much
longer.
One 'wiki-type' site mentions that it isnt just about
feeding, chicks like ducks and chickens may feed themselves but still be
brooded. Alex also brought up the 'more than feeding point'.
There were black ducks at the lake yesterday that were half
the size of their parents but clearly feeding themselves, but still hanging
close to their parents and taking direction from parents when a predator (me)
came along.
So my conclusion was for non precocial species (like
honeyeaters) they were dependent only if I saw them fed, whereas for precocial
and superprecocial (quail??) type species I have put DY if they clearly
seem juvenile, and to be attached to a parent-like bird.
But of course this isnt 'clear'.
Benj
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