If this bird is in essentially adult plumage then the bill having dusky
marks does not rule out an adult non-breeding. The only way to determine if
it is an immature is to look for and I quote from HANZAB "retained remiges,
rectrices and greater upper-wing coverts which should all look worn
(especially the tertials) and contrast with the fresher adult-like plumage".
Cheers Jeff.
-----Original Message-----
From:
On Behalf Of Frank O'Connor
Sent: Tuesday, 10 June 2008 2:31 PM
To: Greg & Val Clancy
Cc: birdswa email list;
Subject: Re: Dollarbird now at Booragoon Lake Perth WA
At 08:24 AM 10/06/2008, Greg & Val Clancy wrote:
>I am curious to know why you believe that the Dollarbird is a 'sub-adult'?
>It look like a juvenile to me. I suppose it depends upon what your
>definition off sub-adult is. Certainly a juvenile is a 'sub-adult' if you
>call anything younger than an adult a 'sub-adult' but I don't. I usually
>reserve the term for a bird that is close to assuming full adult plumage,
>i.e. a late stage immature.
>
>A juvenile bird is one that is still in the plumage that it had when it
>left the nest.
A juvenile Dollarbird has a black bill. This base of the bill on this bird
has started to attain adult colour. The head of a juvenile is
darker. This bird has a brown head very close to adult plumage. A
juvenile doesn't have the blue on the lower throat / upper breast. This
bird has adult plumage here. This bird has more advanced plumage even than
'immatures' illustrated in several texts. So it is older than immature,
but not fully adult. i.e. it is a late stage immature. Ron Johnstone at
the WA Museum agrees.
_________________________________________________________________
Frank O'Connor Birding WA http://birdingwa.iinet.net.au
Phone : (08) 9386 5694 Email :
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