The New York Times had an article some number of years ago about color in
birds, and in it was described an experiment done by Geoffrey Hill of
Auburn. By feeding captive house finches a diet that was alternately rich or
poor in carotenoids, he was able to turn the birds from red to yellow and
back to red. The color in many birds is a function of their diet.

This link should take you to the article, but you may need to register.

http://query.nytimes.com/gst/fullpage.html?res=9407E4DD103AF933A15754C0A9629C8B63&sec=health&spon=&pagewanted=1

--John McKitterick
Columbia, MD
jbmck at comcast.net

On 5/22/07, Jenny McClintock <> wrote:
>
> I posted some photos of the yellow (or orange) variant house finches here:
> http://mywebpages.comcast.net/mcclintock7/yvhf.htm
>
> The quality isn't great ... there wasn't any sun and the wind was swinging
> the feeders. And the brightest yellow male didn't show for his picture
> unfortunately. Maybe I'll get him next time!
>
> Jenny McClintock
> Columbia, MD
>