>I believe the yellow-orange finches are nothing more
>than young males.
>
>--
>Thanks:
>
>James Knapp
>Seattle, WA

Actually, I don't think that's the case. We have birds in the collection
that are fully red but are quite young (conspicuous bursa and partially
pneumatized skull), and I think male House Finches typically acquire their
red plumage by their first winter. We have other specimens that are
yellow-orange but apparently mature (worn summer birds, although specimens
collected many years ago so no age data). Furthermore, I never see
yellow-orange birds at my feeder, but there are lots of juvenile House
Finches each fall (like right now). Finally, there are populations in
California and Hawaii that consist almost entirely of yellow-orange birds.

I think the lack of red represents a dietary constraint, and the literature
on House Finches would bear this out.

Dennis Paulson, Director phone 206-756-3798
Slater Museum of Natural History fax 206-756-3352
University of Puget Sound e-mail dpaulson at ups.edu
Tacoma, WA 98416