Leucistic Fox Sparrow

I first caught a glimpse of this bird a few weeks ago while he was hopping around in the back yard. Then I saw him again at the bird feeder but both times he came and went too quickly for me to capture a photo. I didn't know what kind of bird this was, only that it was something I had not seen before. Yesterday he visited the feeder again and I had my camera nearby to get the above photo. I sought some identification help from a local bird-watcher's site and learned a new word. This is not a new species but a genetic pigment variation known as leucism. The bird above is a leucistic Fox Sparrow. Leucism is a little like albinism but not quite the same. For the technical details I'll refer you to this article in Wikipedia. The small photo to the right is a normal Fox Sparrow.