When bird-eating hawks move in to your neighborhood

Q: I saw what I think was a Cooper's hawk carrying twigs by its feet in early April. We live in a residential area, so they couldn't be building a nest around here, could they?

A: Yes, a pair of Cooper's hawks may very well be building a nest in your neighborhood. These crow-sized raptors, more commonly found in forests, increasingly are looking to cities and suburbs to raise their families. What's the draw? Our bird feeders attract high numbers of birds, and Cooper's hawks survive by eating birds. They favor the larger species, like doves, pigeons, flickers and jays, but I've seen Cooper's hawks snatch starlings and cardinals, as well as juncos and house sparrows, out of my backyard.

If you don't want a raptor hunting through your property, the standard advice is to take down your feeders for a week or more. With your songbirds feeding elsewhere, this should drive the hawk to hunt elsewhere for its meals. But I suspect that if these hawks are nesting nearby, they'll return once you put your feeders back up, since they'll have hungry mouths to feed back at their nest.

Q: I thought chipmunks and squirrels were the culprits eating my beautiful crocuses this spring, but then I spied a house finch eating the flowers one morning. What gives?

A: House finches and goldfinches eat almost nothing but seeds, but they do have a taste for nectar and sometimes visit hummingbird feeders to drink. I'm not sure if the crocus-eating finch was after nectar or roughage, but other readers have reported observing house finches and goldfinches munching on Swiss chard and dandelion greens, as well.

Q: What's the best kind of birdhouse to put up to attract goldfinches?

A: Sorry to say, there's no nest box that will encourage goldfinches to nest in your backyard. This is because goldfinches are not cavity nesters; they build their cup nests in shrubs or tall grasses. In fact, a surprisingly low number of backyard birds in our area will use a nest box, and these include Eastern bluebirds, black-capped chickadees, house wrens, purple martins and tree swallows. Unfortunately, two undesirable, nonnative species, the house sparrow and the starling, often take over nest boxes.

A: The photo you sent shows a large hole in a wooden beam, indicating to me that there's rotten wood inside. The chickadees discovered this and are pulling out scraps of the wood in their tiny beaks in order to construct a nest inside. It could be fun to have chickadees nesting nearby, but if you don't want them there, it would be good to block the entry before they build a nest.

Q: I have a calendar that's illustrated with Minnesota's birds, but I've never seen the waterfowl on the April page and have no idea what it is.

A: I can see by the image you sent that it's a horned grebe, a gorgeous small migratory water bird. These grebes migrate through our area on their way to nesting grounds in Canada and Alaska, and stop over on ponds and lakes along the way, which is why they're a good choice for the calendar's April page.

Q: For the past two years the blackbirds and grackles have taken over my feeders and are keeping all the other birds away. Someone suggested taking the feeders down for a few days, which I did, but the minute I put them back, the blackbirds returned. They eat up every scrap of food and suet, leaving nothing for the other birds.

A: This is one of the thorniest problems for people who feed birds — how to keep undesirable birds out. Many of us, especially those who live near a pond or wetland, have problems with piggy blackbirds. Some experts suggest offering only safflower seed, since grackles seem not to like it. To discourage them from eating suet, you could try one of those suet feeders that compels birds to eat from the underside: Blackbirds can't do this but woodpeckers won't be deterred.

Q: We've had great horned owls nesting in a nearby park and knew that the chicks had hatched out sometime in March. Then in April, during our evening walk, my husband and I heard one of the adult owls giving a sort of muted squawk. What would it have been doing with that call?

A: I asked the expert, Karla Bloem, who heads up the International Owl Center in Houston, Minn. She's studied owl vocalizations and says in April the female owl would have been leaving the owlets alone for longer periods while she hunted at night. The mother owl might make squawking contact with her youngsters while she's away or with her partner, if she feels he isn't bringing in food quickly enough. You can find out more about the fascinating world of owl communication by visiting the center's website (internationalowlcenter.org), then clicking on "hearing individual owls."

Q: He's doing it again — the robin that bashed at our windows last spring has come back and I forget what I'm supposed to do to make him stop.

A: Let's look at this from the robin's point of view: He chased away all his rivals some weeks ago and thought he had established an excellent feeding territory (that includes your property) for breeding season. But one day he spots another robin boldly looking at him, and even after many aggressive displays and even pecking at that robin, it won't leave. So it's up to us to break up the reflectivity of the window he's hurling himself into by placing cardboard on the outside of the window he's using. If this causes the robin to move to another window, cover it with cardboard. This will be a kindness to the bird, who doesn't understand about reflections and can't help himself from trying to drive a competitor out of the neighborhood.

Note to readers: Several of you sent concerns about the homemade suet recipe that recently ran in the paper, relating to the inclusion of bacon fat. This is not a good fat for birds, due to its high salt content and presence of preservatives, so substitute other fats, such as butter or lard.