Subject: More on western tanagers
Date: May 21 11:29:20 2002
From: Maureen Ellis - me2 at u.washington.edu


Mike,
Thanks for following this up; very interesting and important information
about the dietary sources for plumage colors. I'm saving these posts for
future reference! I have included the entire text (not too long) of the
information below. Again, thanks.
Cheers, me2
****************************************
Maureen Ellis, PhD, Research Scientist
Toxicology Group at Roos 1, 284A
Lab/Office phone: 206-685-1938
Dept of Environmental Health, Mailstop 354695
School of Public Health and Community Medicine
University of Washington, Seattle, WA 98195

E-Mail: me2 at u.washington.edu
****************************************
"Why are we now traveling into space? Why, indeed, did we trouble to look
past the next mountain? Our prime obligation to ourselves is to make the
unknown known. We are on a journey to keep an appointment with whatever
we are."_____Gene Roddenberry

On Mon, 20 May 2002, Michael Donahue wrote:

> To add to my earlier posts on head color of male western tanagers...
>
> The Birds of North America account of the western tanager by Jocelyn
Hudon states:
>
> ..."rhodoxanthin produces red hue of head. The latter pigment is
thought to be acquired directly from the diet without modification,
unlike the red carotenoids in scarlet, summer and hepatic tanagers, and
other emberizines [finches], which are believed to be derived
metabolically from common yellow dietary precursors. Rhodoxanthin is an
uncommon pigment in birds, having been reported only in pigeons of genus
Ptilonopus, several cotingas and a manakin. Small quantities of
rhodoxanthins have also been detected in northern cardinal and
orange-tailed cedar waxwing."
>
> He also states that the rarity of this pigment in nature strongly
suggests a dietary origin, but that "preliminary analysis of available
food items have failed to identify obvious sources."
>
> Mike Donahue
> Seattle
>
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