Just to add a little support for my argument....

Here is a link to a photo of a bird that was ID'd in the hand as a
Bicknell's Thrush at the Black Swamp Bird Observatory (BSBO).

http://www.bsbobird.org/graphics/bith1.jpg

To me, the yellow seems to be at least 1/2 of the lower mandible of this
bird, and lacks the rufous tinge in the primaries that are at least
visible.  However, the measurements of this bird were suggestive of
Bicknell's.

Here's another photo from BSBO showing a Hermit Thrush and Bicknell's
thrush side-by-side for comparison.

http://www.bsbobird.org/graphics/bithheth1.jpg

Unfortunately, the head of the Bicknell's is turned so we can't see his
bill, and the lighting is somewhat poor in this photo so the rufous
color in the primaries is difficult to distinguish relative to the rest
of the plumage, though is similar to the color of the Hermit Thrush
pictured.  Hermit Thrushes and Bicknell's are roughly the same size and
both are a bit smaller relative to Gray-cheeked and Swainson's Thrushes.

So this is just food for thought to ponder a bit.....

Do we really have a reliable way of ID'ing Bicknell's in the field other
than voice? 

Just curious what others think.

Casey

Casey Tucker
Education Specialist
Audubon At Home
Audubon Ohio
692 N. High St., Suite 303
Columbus, OH 43215-1585
614-224-3303 (phone)
614-224-3305 (fax)
[log in to unmask]
www.audubonohio.org
 
CELEBRATE Audubon's CENTENNIAL 
I00 Years of Conservation 

-----Original Message-----
From: MU Ornithology Listserv (ZOO 408)
[mailto:[log in to unmask]] On Behalf Of TUCKER, Casey
Sent: Wednesday, September 14, 2005 4:21 PM
To: [log in to unmask]
Subject: DOH!

That will teach me to just look at the pretty pictures...I missed the
text box in between the photos that discusses the importance of the
yellow for separating Bicknell's from the Gray-cheeked in the hand......

However, my question still stands.  Would the amount of yellow in the
bill really be useful for a field ID of Bicknell's?  If not, then is
there another characteristic that could be useful?  Sibley seems to
suggest that the greater amount of rufous in tail and primaries could
potentially be useful for separating the two in the field.  Does this
actually work though?  I've only encountered Bicknell's from afar, and
they were singing on territory at the time.

Kenn Kaufman, in his Advanced Birding guide, discusses the lower
mandibles of various flycatchers as a tool for ID'ing species.  However,
I'm curious as to how many folks use the shape of the lower mandible to
ID non-singing flycatchers even after reading Kaufman?  I'm just not
sure it's useful as an ID tool unless you're either directly below a
bird frozen on a stick, or you have the bird in the hand. Otherwise the
bird is moving around a lot and the bill is in motion & partially hidden
by feathers.

Anyhoo, just my pondering.......

Casey

Casey Tucker
Education Specialist
Audubon At Home
Audubon Ohio
692 N. High St., Suite 303
Columbus, OH 43215-1585
614-224-3303 (phone)
614-224-3305 (fax)
[log in to unmask]
www.audubonohio.org
 
CELEBRATE Audubon's CENTENNIAL 
I00 Years of Conservation 

-----Original Message-----
From: MU Ornithology Listserv (ZOO 408)
[mailto:[log in to unmask]] On Behalf Of David Russell
Sent: Wednesday, September 14, 2005 1:38 PM
To: [log in to unmask]
Subject: answer to quiz birds 14 and 15

Hope this helps.