That's an important question, Brush - how the ID was made. To me it looks like a leucistic Eurasian Collared-Dove. The size is robust, not diminutive; the primaries are dark (given that they are washed out); and I think the undertail coverts are dark (for a leucistic bird). The photo's not clear on this last point. These characters indicate Eurasian Collared-Dove. Leucistic birds are not rare given the small source population. http://home.earthlink.net/~sonoranaturalist/id32.html has one photo showing some differences between these species. Mary Gustafson Mission, Texas