It is thought by ecological physiologists and behavioral ecologists that
male house finch color may be correlated with quality of diet. The more
successful males are brighter and redder, and seem to be preferred by the
female house finches. The orange or yellow birds may be less experienced
or just less successful at finding a good diet or may be basically less
healthy. There are papers in the behavioral ecology literature
that provide supporting evidence for the good food = nifty-colored plumage
idea.
Maureen E. E me2 at u.washington.edu DesMoines, WA and U of WA
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On Sun, 5 Jan 1997, Susan Treu wrote:

>
> Hello all;
>
> I have been observing numerous house finches over the last few weeks and
> wonder about the color variations. I've looked through the few bird books
> on my shelves but don't find an answer. Can anyone briefly explain the
> how and why of the wide color variations? I have observed many with the
> different shades of red color but have also seen several with a golden
> yellow wash in place of the red markings. (not as crisp as gold finches)
> Just a few minutes ago I was treated to a single individual that
> sported a bright citrus orange color, both on head and tail area!
>
> Thanks--Susan
>
>
>
>