Q My cardinals look so dull this fall; could their diet be deficient?

A Cardinals begin molting a new coat of feathers at the end of summer and complete the job by early November. The males look a bit dull once the molt is completed, because the new feathers on their backs are tipped with gray, dulling the red. This color will wear off over the winter as the birds endure storms and rub against vegetation, leaving the males with brilliant red feathers just in time for the breeding season.

Night dorms

Q I'd like to build a box for birds to roost in at night; do you know where I can find some plans for this?

A The kinds of birds that build their nests in cavities (chickadees, bluebirds, nuthatches, etc.) will also roost at night in tree holes or boxes. There never are enough natural cavities to go around so building roost boxes is a good idea. There are a number of Internet sites that provide plans for building such a box.

You might start with the Cornell Lab of Ornithology's: www.allaboutbirds.org/page.aspx?pid=1144; the Audubon Society of Omaha also has plans: audubon-omaha.org/bbbox/nestbox/fawzirb.htm. Another excellent source is the build-it-yourself book by the Minnesota DNR's Carrol Henderson, "Woodworking for Wildlife 3rd edition," available at local bookstores and online.

Hands off nests

Q You recently wrote something that made it sound like it's illegal to keep a bird's nest -- is that true?

A Yes, it is true. The International Migratory Bird Treaty Act makes it illegal to possess migratory birds, their feathers, eggs and nests. The law has been on the books for nearly a century and was designed to stop the market hunting of migratory birds and their wholesale slaughter for human adornment (women's hats used to feature feathers and nests, for example). Back in the early 1900s many bird species' populations were severely declining because of overhunting and egg and nest collecting.

So it's pretty much "hands off" these days except for those species that are legally hunted. However, the reader who wrote in about a phoebe nest wanted to help the birds by cutting their nest back a bit, and since there was no intent to possess the nest, he was within the law.

Duck soup

Q I thought eagles were fish eaters but lately I've seen a bald eagle swooping down over flocks of coots in the water. Others have told me they've seen this, too.

A You're right, fish make up a large proportion of an eagle's diet and this explains why the big birds stack up along open waterways in the winter. But they're always on the lookout for an easy meal, and a coot or duck that's sick or injured and unable to escape makes for a good snack. An eagle will strafe flocks of waterfowl in the fall to see whether any fail to fly away or dive. If there's a likely prospect, the raptor will circle back to pick up its prey.

Crane dances

Q I have the enjoyable experience of being able to observe sandhill cranes in a field I pass on my way to work. They were doing what looked like a courtship behavior, even though it was early fall, so I'm wondering what they were up to.

A Researchers have found that sandhill cranes dance all year long and, outside the breeding season, this may help to relieve aggressive feelings. A group of young cranes may often become excited or stressed and express this by dancing. Some crane experts even suggest that cranes may sometimes dance for the pleasure it gives them. We might not know all the reasons that non-breeding cranes engage in dancing, but it is a lovely sight.

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

In the wintertime chickadees sleep inside cavities, either within trees or in roost boxes supplied by humans.