Probably half of the albinos I have seen have been house sparrows, and I
always assumed that had to do with their introduced origin. A small
founding population could mean less genetic variability, which increases
the possibility of a bird inheriting the same genetic defect from both
parents. 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. I have also seen a starling with
a white tail, though he was the only albino starling I ever saw. House
Finches in the Eastern U.S. would make a good test of my suggestion:
founding population of only 40.

Chris Hill
Seattle, WA
cehill at u.washington.edu