Look for eagle eggs to hatch in March

Q: When do eagles start their nesting season? I recall that the pair on the DNR’s eagle camera were sitting on eggs in January one year.

A: You’re right about that widely watched DNR webcam nesting attempt in January 2013, but those “early birds” were really pushing the season and their nest wasn’t successful. Most eagles in our state begin egg-laying in February, the young hatch in March and are fledging by late June.

View the Minnesota DNR eagle webcam here: dnr.state.mn.us/features/webcams/eaglecam/index.html. Keep in mind that the nest fell during a storm last April, so the camera now shows the former nest area, with the eagles in occasional view as they defend their territory.

Q: I have a problem with goldfinches: I counted 25 at one time on my feeder and sitting in nearby trees. They sit almost all day at the “lunch counter” and can empty out the feeder in two days. Any ideas for how to deal with that?

A: Many of us who feed backyard birds would be envious of what’s obviously a success story at your feeders. OK, it may be a bit costly, but goldfinches are fun to watch and winter is the time when they need all the calories they can find. My only suggestion is to change your own outlook, and recast this as a good thing instead of a problem. You’re providing vital food for a desirable species and they’ll surely disperse when spring rolls around.

Q: Walking around my neighborhood on a winter day, I watched two crows tearing apart squirrels’ nests in two adjacent trees. I haven’t seen this behavior before, and wondered if they were attempting to reach recently born squirrels. Any ideas?

A: That’s an interesting question, and I once observed similar crow behavior in a park near my home, with crows tearing apart an old squirrel leaf nest, chortling and chattering as they worked. My suspicion is that in both cases the crows had either discovered a dead squirrel or a storage place for nuts and other foods made by a red squirrel, blue jay or other creature. I checked with the Wildlife Rehabilitation Center and it had no infant squirrels that early in the year, so the crows probably weren’t eating youngsters. Executive Director Tami Vogel suggested that the crows might have discovered a food cache or simply be exercising their corvid curiosity — having once found food in a squirrel nest, they now check them out, on a regular basis, just in case. And as you know, crows are always up to something.

Q: Is there any real benefit to birds in having access to bird feeders?

A: Longtime feeder of birds, author and nature observer Don Grussing of Minnetonka recently sent an interesting news item which indicates that there is a real benefit: “The Journal of Animal Ecology reports that birds with regular access to feeder food could maintain lower body temperatures, and this helps them live through cold nights and use less energy to fight off infection.” Birds in the study that lacked such access had to burn more energy to raise body temperatures to fight infections, which made them more susceptible to the cold.

Q: I never see owls. Are there tips for finding them?

A: The easiest way to find an owl is to hear it, says Kevin McGowan, an educator at the Cornell Lab of Ornithology in Ithaca, N.Y., then track it down. The rub is that most owls are active (and most vocal) at night) so if you don’t want to be out after dark, another tip for finding them is to follow the sounds of birds making a big racket in the daytime. Quite often this will lead you to a tree where an owl (or hawk) is being mobbed by smaller birds trying to drive it out of the area. Most of my own owl sightings have come this way.

Q: My nephew asked me a question I can’t answer: What percentage of birds are monogamous?

A: Excellent question about a topic that looms large in the avian world. Bird scientists are continually learning about birds’ breeding habits, and the current thinking is that 90% of birds are monogamous, defined as having a pair bond between a male and female. (Monogamy is quite rare in the mammal world, with less than 5% of mammal species pairing up to raise their young.) Monogamy works well for birds in raising a brood of youngsters and may last for a single breeding season, several seasons or for life. However, keep in mind that monogamy in the bird world is often not the same as in the human world. Many bird species hedge their bets by mating with others even while nesting. This occurs both with males and females, and it means that some eggs in a single nest might have mixed parentage: There might be eggs fertilized by two (or more) different fathers, or two females may have deposited their eggs in the same nest. With advances in genetic analysis, we’re learning more all the time.

Reader feedback: After a recent column devoted to Northern flickers, reader Kim Gordon of Minneapolis sent this interesting anecdote: “A few winters ago my neighbors had a throw rug hung over their porch railing. This caught the morning sun and every morning a group of flickers would come and clutch the rug and hang in the sun together. It was so interesting to watch from my window, but at some point, the neighbors moved the rug and the flickers moved on.”

Hannah Owens-Pike of Minneapolis noted a recent question-and-answer about attempts to control box elder bugs indoors: “My cat loves to catch and eat them. Anytime she sees one she’ll chase after it and eventually eat it. Just a thought about another way to get rid of the bugs after they make their way inside.”

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 valwrites@comcast.net.