Q: In the past I would sometimes see mourning doves in winter in Minnesota: This year, for the first time, I have from 10 to 12 doves picking up seeds under my feeders. Is this common or is it another sign of the warming of our planet?
A: That must be quite a sight in the morning and evening in your backyard. It's not unusual for members of this species to winter over in our area: In fact, in other winters, I've often had five or more doves sitting on the rim of my heated birdbath at dusk, just before disappearing for the night. Several other readers have also written about the doves they're seeing this winter. These birds seem to be a bit nomadic, so if they visit a backyard one winter, they may go somewhere else the next year.

Owl food
Q: I've sometimes observed eagles and hawks scavenging a carcass. Do owls ever scavenge?
A: That's an excellent question, and for an answer I turned to owl expert Karla Bloem, director of the International Owl Center in Houston, Minn.: She says it's rare for an owl to feed on a dead carcass, but it does happen. "I suspect it is only when they aren't catching enough on their own. In high school I once observed a great horned owl feeding on a road-killed deer daily for about a week in winter — this was the first photo I ever took of an owl," Bloem said.

Mystery bird
Q: A bird is frequenting my backyard, but I can't find it in my field guide. It's about the size of a red-bellied woodpecker and has a long, pointed beak. Can you help?
A: The photo you sent shows a bird that confuses many of us at this time of year because its plumage is so different from its summer look. European starlings in winter have white-tipped feathers, making for a dramatic pattern on their backs and wings. Over the winter these tips will wear off and starlings will show all black plumage for the breeding season.