We have some friends who live south of Grand Rapids, Minnesota. A Robin built a nest under their deck. When the babies fledged, our friends discovered that two of the juveniles were albinos. One study that is often sited found that, among North American bird species, Robins had the highest percentage of albinos. I think it is very unusual to have two in one brood, but an Internet search found at least one other instance when this happened. I couldn’t get very close to the albino Robins, but I did get photos of both birds that showed they had pink eyes, a sign of true albinism.