[Tweeters] Nancy Morrison's leucistic Fox Sparrow

[Dennis Paulson via Tweeters]

Gary, thanks for all the info, very interesting. While not quantified, I think I have seen more leucistic Black-capped Chickadees than any other species, with Dark-eyed Juncos in second place. But like you, I’ve seen leucistic individuals of quite a few species over the years. Leucism has been a genetic factor in our black-caps over the years, and I have never seen a leucistic Chestnut-backed, just as common at our feeders.

And of the small birds, I suspect we are biased toward species that come to feeders.

Dennis Paulson
Seattle


> On Feb 6, 2026, at 11:17 AM, Gary Bletsch via Tweeters <tweeters at u.washington.edu> wrote:

> 

> Dear Nancy and Tweeters,

> 

> That is a nice photo of a leucistic Fox Sparrow, taken by Nancy Morrison. Cool-looking bird!

> 

> From what I've seen, leucism occurs in Fox Sparrows more than any other species of Washington State bird that I can think of. I have been keeping track of this for a long time. Here are statistics of observations of leucistic species.

> 

> Fox Sparrow, 8 leucistic out of 1797 observations, or 0.445%;

> 

> Dark-eyed Junco, 26 leucistic out of 10,150 observations, or 0.256%;

> 

> *Red-tailed Hawk, 16 leucistic (?) out of 9255 observations, or 0.173%, but this one does not count, because I think a lot of my early observations of what I thought were leucistic Red-tails were actually light-morph Harlan's Hawks, and many of these 16 sightings were repeats of the same bird;

> 

> Red-winged Blackbird, 21 leucistic out of 12,201 observations, or 0.172%; several of these were the spectacular birds that I like to      call "Giant American Redstarts";

> 

> *Bald Eagle, 10 leucistic out of 7899 observations, or 0.1265%, but this one does not count, since most of the observations were of

>        repeats of the same bird;

> 

> American Crow, 21 leucistic out of 18,521 observations, or 0.11%; most of these were the crows with what I call "Willet-wings", a           variation depicted in the Sibley guide;

> 

> House Sparrow, 10 leucistic out of 10,780 observations, or 0.0927%;

> 

> Canada Goose, 6 leucistic out of 6698 observations, or 0.0896%;

> 

> American Robin, 14 leucistic out of 20,668 observations, or 0.0677%; 

> 

> European Starling, 9 leucistic out of 19,866 observations, or 0.0302%;

> 

> Brewer's Blackbird, 13 leucistic out of 5720 observations, or 0.0174%;

> 

> Song Sparrow, 2 leucistic out of 14,993 observations, or 0.0133%.

> 

> 

> In all, I've noticed leucism in 45 species of birds, but most of those were just one observation in a particular species. It seems to be a rather rare phenomenon, except in certain groups, such as New World Sparrows, Icterines, and waterfowl. 

> 

> Probably the coolest one I've seen was a Cream-winged Cinclodes, way up in the Andes. The guide and the other birders in the group were mystified for quite some time as to the identity of that bird, which sported an all-white head!

> 

> Thanks to Marv Breece for getting me squared away on the light-morph Harlan's.

> 

> Yours truly,

> 

> Gary Bletsch

> 

> PS Now I've been in Western New York for almost three and a half years, and have still not observed any leucistic Red Fox Sparrows. Then again, Fox Sparrows here are a rather uncommon species, unlike in Western Washington, where there seems to be one in every blackberry tangle in wintertime.

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