That "a baby bird is known to imprint on its parents" applies to many species.
Most obviously things like ducks. It does not apply, to many other species.
Clearly not for cuckoos. Cuckoos clearly know who is their species when it
comes to mating. Besides the size difference is usually extreme and there is no
resemblance of foster parent victims, to themselves, as adults. In some species
it applies more to one sex than the other. For some species the males will
imprint onto a foster parent and court females of that species when mature but
females still know what is the right species when they grow up.
As for "why don’t Currawongs identify the cuckoo as an imposter?" There is
probably a multitude of reasons for many different species. A simple answer in
many cases is they do. However the cuckoo has evolved counter measures of being
overly enticing to the parent. Like a very big mouth that the foster parents
find hard to not feed.
As interesting as these questions are, in a way they are more interesting for
the brood parasites that parasitize similar birds, like in the finches (Whydahs
and Waxbills) and the at least one species of duck that parasitises other
ducks.
Philip
-----Original Message-----
From: Birding-Aus On Behalf Of
Chris Melrose
Sent: Tuesday, 19 December, 2017 1:24 PM
To: Birding Aus
Subject: Channel-billed Cuckoo
Hi All
I have a few Channel-bills that have parasitised Currawong nests near my home
on the lower north shore of Sydney. Numbers seemed to have increased over the
years and they are even now along the Central Coast of NSW in places not
previously seen.
This week I can hear adults interacting vocally with fledglings, although I’m
never in the right place at the right time to see the interaction. My question
is: if a baby bird is known to imprint on its parents, the cuckoo should
imprint on the Currawong when it is born, how does this imprint change for
fledgling cuckoos so they later identify with adult cuckoos? What are the adult
cuckoos doing when they come to visit the fledgling? And finally, why don’t
Currawongs identify the cuckoo as an imposter?
Do birds identify with others of their species? The ones in my neighbourhood
always tend to stick together, so what is it that allows this switching of
identity to happen?
Cheers
Chris
Christine Melrose
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