I like Dennis' theory a lot, but my personal slightly whimsical
hypothesis (while buried in student papers and exams at the end of finals
week) is that all of us caretakers of birds using bleach and hot water to
clean out the bird baths are leaving trace elements of same causing the
white feathers on chickadees and the like to turn white.
JoLynn Edwards
Asst. Professor
University of Washington, Bothell
jolynn at u.washington.edu

On Thu, 16 Mar 1995, Dennis Paulson wrote:

> When I was in London many years ago I noted an amazingly high frequence of
> partially albinistic birds, and my hypothesis was that these birds existed
> in the city because there were few bird predators to home in on them.
> Albinism is probably selected against rapidly in nature, so we probably see
> a lot fewer of them than hatch out of eggs.
>
> That hypothesis is still valid, but an alternative one to consider is that
> some dietary lack or inbalance is manifesting itself in these birds that
> spend all winter at bird feeders. I know wild birds in captivity sometimes
> change color at a molt.
>
> 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
>
>
>