Q: I noticed a crow on top of a deciduous tree pulling and twisting a twig until it broke loose, then the bird flew into a spruce tree, where I assume it had its nest. I always assumed crows built their nests from dead twigs, and wonder if this crow was normal.

A: Very normal, according to Kevin McGowan, an educator at the Cornell Lab of Ornithology, who’s been observing crows for decades. He says, “If there are enough trees around, American crows use only freshly plucked twigs in their nests. I have never seen a crow pick up a stick from the ground, and in fact, if a crow drops a twig it just broke off, it leaves it and plucks another one. This habit of theirs is very useful for our research on nesting crows: We can tell a new nest from an old one by noting if there are freshly broken stick ends.” McGowan noted that crow nests are a challenge to find, since they tend to be high in trees and well concealed.

Mating urge

Q: I’ve been wondering whether birds “go into heat.” How do they know when it’s time to mate?

A: That’s an interesting question, and while avian breeding differs from mammals’ reproductive cycles, birds do experience an intense interest in mating in springtime. It’s a hard-wired response to days becoming longer, inspiring their bodies to increase production of the hormones that prepare them for mating. Among songbirds, a male’s singing helps synchronize a pair’s interest in breeding. In our area, some birds, such as robins, bluebirds, cardinals and house finches, even raise two broods (and sometimes more) during the breeding season. Birds have evolved to breed at a time when their food is abundant, so you can see how our warming climate may affect nesting success: Nearly all songbirds feed their youngsters insects, a good source of protein that promotes quick growth. If insects start to hatch earlier, due to earlier warmer weather, there may not be adequate food for nestlings.

Sick bird

Q: A very sick looking brown and red bird was sitting in our feeder the other day and seemed to have something wrong with its eyes. Do you know what was the matter?

A: The sick bird in your feeder almost surely was a house finch infected by avian conjunctivitis, an eye disease caused by bacteria. The disease first showed up in Minnesota house finches in 1996, and led to the death of many birds. As they developed immunity, the disease evolved and has become more virulent. The best thing to do now is to clean feeders well and rinse with a solution of one part bleach to nine parts water, then wait a few days (hoping the bird will leave) before putting the feeder back outdoors. Rake beneath feeders to remove droppings and old seed, and please keep an eye on the situation: If any other birds with swollen, crusty eyes show up, take the feeder(s) down again for some days, and wash and rinse thoroughly. This is a serious disease that has also been found in goldfinches and some other species, those that crowd together to feed.

Wayward builders

Q: Why do birds keep rebuilding nests in the wrong places? Some bird keeps building a nest above my front door, and leaves a big mess of poop and mud and grass on the steps. Some other birds keep building nests in my hanging baskets. Is there anything I can do to entice them to go elsewhere?

A: It’s tough for birds to find nesting sites that offer both stability and protection, and once they do they can be incredibly persistent. The only surefire way to prevent further building on that ledge is to put something up that deters the birds, possibly chicken wire, pieces of cardboard or a device that whirls in the wind. The birds in your flowering baskets are probably house finches; they love these because they provide cover for a nest and nestlings. I’ve heard from a number of readers who coexist with house finches in their hanging baskets, watering carefully around the nest as long as it’s occupied. I hope these tips work for you.

Full feeder awaits

Q: I recently purchased my first bird feeder and installed it and a suet holder on a shepherd’s hook. We live very near a nature reserve that’s full of birds, but none of the local birds have visited the feeders yet. What am I missing?

A: Good for you for joining the ranks of people who feed birds. Don’t fret that you’ve had no visitors yet, as it sometimes takes a while for birds to come to a new feeder. One reason is that bird feeders are not part of the natural world, so birds may not initially recognize that these offer a meal. But soon, a bird, probably a fearless chickadee, will fly in to investigate, others will notice, and more will follow. During nesting season, adult birds are raising their young on an insect diet, whose protein helps nestlings grow quickly. Once young birds leave the nest, they and their parents will be on the lookout for seeds and suet.

 

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.