One of the hazards of feeding birds is that predators sometimes snatch one of the birds you've been fattening up.
I went out to refill feeders and found evidence of at least an attempt to catch one of my doves. I did not find a carcass and dove feathers pull out very easily, so I cannot say for sure this guy is a goner. However, judging from the number of feathers in this area, if he wasn't a casualty, he's darn cold.
Since I didn't find evidence of a carcass, I would assume one of the feral cats that live in the field next to my house probably got lucky. If the cat caught one of the white-winged doves, he should be stuffed for a week.