Unusual Bird: White robin

This bird was first seen in November 2013. We didn’t know what it was until a naturalist from a nearby state park came by and helped us identify it. It stayed around for about 2 weeks in a sycamore tree eating wild grapes. It was alone most of the time until some other robins came by. Then it left and was gone all winter until two days ago on February 21,2014. I spotted it in a neighbors yard. I have seen it three times since.We were very excited to see it because I didn’t think we would ever see it again.