Jeewa sent me this photo taken at FWG today and wondered if this was an albino bird. At first that is just what it looks like, but then you notice the darkish feathering and the brown eyes. Leucism is a lack of pigmentation and birds may be wholly or partially leucistic. I believe it is caused by a genetic mutation. I have seen a few such birds, most recently a white-throated sparrow in the spring. It is always quite sensational to see these very peculiar looking birds!