Q: I'm seeing old bird nests everywhere, now that there aren't any leaves. My question is, why didn't I see the activity of the parent birds coming and going to these nests last summer?

A: It's a surprise to see how many birds raised their families among us, as indicated by the number of old nests now blowing apart in trees and shrubs. The reason you weren't aware of the parent birds as they engaged in nest building, then feeding and cleaning up after their offspring, is that birds become very secretive during nesting season. They know that predators are eager to find the easy meal that eggs and chicks would provide, so they keep their activities hidden as much as possible. As they come and go to the nest, parent birds continually change their approach routes and are nearly silent.

'Flagbirds'

disappearing

Q: It's been 30 years since I last saw a red-headed woodpecker. They used to be common and we called them "flagbirds." Are their numbers down?

A: You're right, few of us see these dramatically colored woodpeckers anymore, since their population has declined by 90 percent over the past 40 years. That dramatic downturn means something is very wrong, and all fingers point to loss of habitat. This woodpecker prefers to nest on oak savannas in dead trees or tree limbs, but this kind of habitat is becoming fairly rare. Find out more about the Red-headed Woodpecker Recovery Project here: www.redheadrecovery.org.

Strange orange birds

Q: There have been some odd birds at my feeder, about the size of a goldfinch but with the orange breast and head of a robin. Are these goldfinches acquiring their winter color?

A: I'd bet that those orange-breasted birds are house finches — there's a great deal of color variation in this species, from the normal bright red to orange to yellow. Their feathers are colored by the foods they eat, so the orange-y birds at your feeders may not have consumed enough red berries last summer.

Chickadee circuit

Q: My chickadees seem to come in flocks: Six to eight of them show up within minutes of each other, and then disappear in the same way. It's as if they're going around on a route pattern they all know. Your thoughts?

A: You've described very well how chickadees move around in winter, traveling in small flocks around a circuit, stopping at feeding sites along the way. Your feeders are part of their regular feeding route and they probably drop down several times a day to refuel. And since they maintain hierarchies within the flock, the most dominant bird will feed first, followed by those of lesser rank.

Predatory jay

Q: I looked out the window the other day and noticed that a blue jay was pecking at something, which turned out to be another bird. It flew off with either a nuthatch or chickadee clutched in its feet. Is it common for jays to be so aggressive with smaller birds?

A: Duluth naturalist Laura Erickson, who has spent years studying blue jays, has found that they're opportunists: If a small bird hits a window and lies stunned below, a jay might swoop in to carry it off. She's never seen a blue jay take a healthy bird, so suspects something was wrong, either due to injury or illness, with the bird it took in your back yard. Their regular diet is almost entirely seeds, nuts and fruits.

Bird-free bath

Q: I installed a birdbath heater two weeks ago but have not had any birds coming to drink from it. I wonder if they're scared of it or what else is going on.

A: Once they get used to it, your back-yard birds are going to appreciate that heated birdbath. Birds are very cautious about anything new — they have to be, since there are so many dangers in their world. They may not realize yet that the new thing in the yard holds water. Some bird, probably a curious chickadee, is going to have to "break the ice," and drop down for a drink. Other birds will notice and follow suit.

Please keep a wooden board handy to put over the center of the birdbath on very cold days. This will allow birds to drink but prevent them from bathing to refresh their feathers, which could lead to death by freezing.

Small dogs and eagles

Q: Now that eagles are becoming almost plentiful in the metro area, how safe is it to let our small dog out in the back yard?

A: Many people have inflated ideas about the size of prey that bald eagles can catch and carry. People repeat stories about eagles taking young sheep or calves, as well as cats and dogs. But please consider that the average bald eagle weighs between 8 and 12 pounds, and is said to be capable of lifting about half its body weight. This means it can carry between 4 to 6 pounds, and most small dogs weigh more than this. I'd say your little dog is safe.

St. Paul resident Val Cunningham, who leads bird hikes for the St. Paul Audubon Society and writes about nature for local, regional and national newspapers and magazines, can be reached at valwrites@comcast.net.