Last week while I was sitting at my desk I saw a huge flash of white out of the corner of my eye as a couple of Mourning Doves flew down to the base of my feeder. Since White-winged Doves can show up anywhere in the US, I'm always half-way looking for them. I rushed to the window to check out the dove only to be confronted by this guy (on left).
A Mourning Dove with white tail feathers. Just goes to show you have to double check those field marks when you get a quick look at a bird--and need more than one field mark to ID a bird. In this case a bird with a few white feathers can superficially mimic a well-known field mark of another species. According to the Birds of North America account, partial albinism like this is rare in Mourning Doves and usually involves wing feathers.