Q: I’ve read about winter roost boxes for birds and have heard that many kinds of birds will gather in them at night to share body heat. Are they a good idea, and are they available locally or do we have to build one?

A: That’s a very timely question, since roost boxes are designed to help cavity-nesting birds make it through winter nights. Many such birds will sleep in a nest box (bird house), but a roost box conserves a bird’s heat better by setting the entrance hole low on the front. And dowels inside the box provide perches for several birds, allowing them to share their heat overnight. This might appeal to birds like chickadees, woodpeckers, nuthatches, house sparrows, starlings and screech owls. (We had a roost box attached to a big tree in the back yard for a number of years but I never once saw a bird enter or leave this structure.) Roost boxes are available locally at wild bird supply stores and you can find directions for building them at http://tinyurl.com/cmb78ud (scroll down). Also check out the plans for a chickadee winter roost box in Carrol Henderson’s “Woodworking for Wildlife,” 3rd edition.

No red birds

Q: We’ve always had lots of cardinals coming to our various feeders over the years. But starting this fall I noticed I hadn’t seen any cardinals for several months. What could have happened to them?

A: It’s a shame you’re not seeing any cardinals at your feeders. I wonder if the birds you’re used to seeing moved away from your back yard during the breeding season, then found other sources of food as the weeks passed. This is how it works in my back yard: The cardinals disappear in the summer and early fall, then start appearing again on or below the feeders sometime in late October. In January and February we sometimes observe 15 or more red birds gathering near the feeders late in the afternoon. I hope by now you’re seeing cardinals again, watch for them early in the morning and late in the day.

Dove oasis

Q: We have a heated bird bath and like to watch the mourning doves gather at dusk around the rim. They seem to enjoy the warm steam that comes off the water and then they stick their heads right into the basin. Why do they do that?

A: I think you’re right, that the doves come in to warm up a bit around the birdbath before nightfall. I enjoy watching them at my birdbath late on winter afternoons, they seem to enjoy each other’s company and a respite from the cold. That head-dunking thing is how they take a drink of water. Doves drink by submerging their heads almost up to the eyes and then using their throat muscles to pump up water. Songbirds drink in an entirely different way, dipping their beaks into water, and then lifting their heads to tilt the water down their throats.

Band data

Q: I’m wondering whether you keep track of banded birds? I watched one all summer and wondered about where the band came from.

A: There’s an agency within the federal government that tracks banded birds. If you can read the code on the band, you can ask the Bird Banding Laboratory for information about that bird. It’s on the Web at: http://tinyurl.com/ll86lng.

Birds and paint

Q: I’m building several bird feeders for friends and am thinking of painting only the outsides. Is this the correct thing to do?

A: Yes, I think it’s safest for birds if you leave the insides of the feeders unpainted, then there will be no worries about chemicals leaching into the bird food.

Blues in the cold

Q: One day in mid-November I was surprised to see our back yard swamped with bluebirds. Twelve of them were fighting over the bluebird houses and wood duck house. I thought they left for the winter.

A: You’re right, bluebirds are migratory — they’re known as short-distance migrants, since they only go as far as the South (or Mexico) for the winter. Since they don’t travel far, they don’t need to leave our region as early as birds that travel long distances. I’ve often heard reports of bluebirds checking out nest boxes before they depart in the fall, and the theory is that they could be planning where they’ll nest next spring. That might be what the flock you saw was doing. Another possibility: In cold weather, bluebirds are known to huddle together at night in a nest box or tree cavity. I wonder if at least some of the birds you saw had slept in the boxes overnight and were then competing with newly arrived bluebirds for “ownership” of the structures.

Night raiders

Q: I’d like to add to the list of varmints that might clean out a bird feeder at night (in addition to raccoons and flying squirrels). I just happened to look outside one night and saw several deer around the feeder. One of them would hit it with its nose, and the others would eat the spilled seed. The same thing happens at my neighbor’s feeder, so this is more common than people think.

A: You are so right, deer can empty bird feeders very quickly. And since deer are becoming more widespread in the metro area, this is an excellent tip.

Condor cam

Q: I really liked watching bird cams on my computer last spring and summer. It’s tough to have to wait until next spring for more up-close views of birds. Any suggestions?

A: Several bird cams are up and running through the winter, so you don’t have to go cold turkey. One of the more interesting is the “condor cam” at a sanctuary in the California hills. You may catch North America’s largest bird feeding, grooming or flying at www.ventanaws.org. Or try the camera focused on birds coming to feeders at the Cornell Lab of Ornithology, http://tinyurl.com/klphzgv or at a busy feeding station in Ontario: http://tinyurl.com/m7f6pjm.

Bad glass

Q: Right after I read the column about red-breasted nuthatches, one hit my window near the suet feeder. It lay on the deck for some time but after about an hour had flown away. Do birds recover after hitting a window and are unconscious?

A: Windows are a major hazard for birds — they kill or maim millions of them every year. Even if a bird is able to fly away it may succumb to its injuries later, and if it has damaged its beak, which often happens, it may slowly starve to death. Since your window has been involved in at least one window strike, it would be helpful to birds to make it more apparent. I’m a big fan of the static-cling window decals sold by WindowAlert, since they’re nearly invisible to humans but reflect ultraviolet light, so are seen by birds. Please also consider the “Rule of 3/30”: Place feeders very close to windows, so birds flying away don’t build dangerous momentum, or 30 feet or more away, so they have time to notice and avoid a window.

Flock fear

Q: A group of geese were grazing in the park behind our house when they suddenly flew up and landed in the nearby pond. A little later I noticed a bald eagle sitting on the ground where they’d been. Are geese afraid of eagles?

A: Even though they’re large themselves, Canada geese have an instinctual fear of big, flying predators. When they saw the eagle flying overhead they headed for greater safety in the water. And the fact that they all were able to fly showed the eagle that there was no easy prey in this group of geese.

 

St. Paul resident Val Cunningham, who volunteers with the St. Paul Audubon Society and writes about nature for local, regional and national newspapers and magazines, can be reached at val​writes@comcast.net.