Subject: [Tweeters] Leucistic bird sightings Date: Sun Nov 17 16:06:48 PST 2019 From: Dennis Paulson - dennispaulson at comcast.net
I have had leucistic Black-capped Chickadees in the yard just about every year since we moved here in 1991, on occasion more than one. I think it has been a dozen or so birds over time, with all different patterning of white feathers. I don't know about the inheritance of leucism, whether it is a gene that can produce white feathers anywhere, or whether there is more than one gene acting to withhold pigment from feathers on different parts of the bird. Can the same bird have a different distribution of white feathers over its life time? We need banded leucistic birds. Black-capped Chickadees live on the average 2-3 years, with the oldest recorded 12.5 years.
We've had a number of them with white outer tail feathers (which I called juncadees), some with part or even much of the black cap white, and quite a few with largely or even entirely white backs. The wings seem to be resistant to the gene, which is good, as feathers without pigment are weaker than those with it. Too bad we can't send attachments on Tweeters, as I have photographed many of them.
I don't know if this is germane, but many years ago when I visited Hyde Park in London, I was amazed at the number of leucistic birds of a variety of species. I speculated at the time that it was because there were no predators acting as agents of natural selection to eliminate the mutation. Could that be happening in our cities?
> Just got around to getting my photos in order and wanted to respond to Peggy Mundy?s sharing of seeing a leucistic Black-capped Chickadee in her yard (back on 6 November). I find such reports of interest because this past year I have documented 5 individuals of 4 different species of bird, that exhibit what appear to be leucistic plumage markings. Several years ago, we had a couple of leucistic chickadees in the yard for a couple of years, then hadn?t seen any for several years. Since last winter we have had 2 different apparently leucistic chickadees (one to a much greater degree than the other) as well as an American Goldfinch, a male Spotted Towhee, and a male Northern Junco, all with atypical whitish markings on, at the least, their heads. For those interested, photos can be seen in my Flickr album Leucistic Birds: https://www.flickr.com/photos/danenewarnock/albums/72157710859201313 <https://www.flickr.com/photos/danenewarnock/albums/72157710859201313>.
> I find this somewhat interesting and strange, to see such a surge of sightings in short timeframe; I am interested to learn more if others have something to share about this phenomenon. I know of at least one other person in the area (but not particularly close to my neighborhood who also saw a leucistic Black-capped Chickadee in their yard this year, which looked very similar (but not identical) to one of those frequenting my yard.