Christopher Hill says,

> Those who breed colonies of zebra finches in captivity tell me
> that, if they start with all normal colored birds, in only a few generations
> albinos start popping up spontaneously.

Interesting. We can't generalize much from one species, but this implies
that natural populations can harbor recessive mutations for albinism that
only start to show up with inbreeding. That would explain a lot of the
albinism that people are reporting. Are city populations likely to be
more inbred than others? An urban population of English Sparrows
probably is. Urban Rock Doves? Maybe a small group of chickadees that
find a wooded urban patch hospitable and tend to stay and breed there.
The genetic hypothesis is worth considering along with the others.

Burt Guttman guttmanb at elwha.evergreen.edu
The Evergreen State College Voice: 360-866-6000, x. 6755
Olympia, WA 98505 FAX: 360-866-6794