Does treating ashes for borers harm birds?

Q: My ash tree has been undergoing emerald ash borer treatment for several years. Does the chemical injection affect the woodpeckers and nuthatches? I hope I’m not inadvertently poisoning them.

A: That’s an excellent question, and in researching an answer I was directed by the state Department of Agriculture to a fact sheet prepared by insect experts at several universities, including the University of Minnesota. They conclude that the chemicals used to treat ash trees pose little threat to woodpeckers because the birds bore into bark to feed on living insects, not on dried up insects killed by insecticides. The researchers also say the emerald ash borer chemicals don’t bio-accumulate in animals (the way DDT did) and that woodpeckers search for larvae in the outer bark, where the insects aren’t exposed to systemic insecticides. All in all, it seems safe to say that your tree treatments aren’t harming woodpeckers and nuthatches.

Q: I’ve always wondered what determines which birds migrate and which stay, and whether this changes from year to year. Can birds just decide not to migrate?

A. Good question about a topic that fascinates many of us. A lot of research has gone into bird migration so we know that the birds that leave our area in the fall — 75% of the species we see in summer — are motivated by the approaching lack of food. These primarily are the insectivores, birds that live on insects, including bluebirds, kingbirds, warblers, robins, swallows and others. Cold weather kills off their sources of food, so they fly south to areas that have arthropods and insects available all year. Many of these birds would be hardy enough to survive our winters, but they can’t survive without food, so they’ve evolved to migrate on a regular schedule. Migration is not a choice, but a necessity. Migratory birds’ bodies go through changes as days get shorter and they can’t ignore hard-wired imperatives to put on weight and embark on their southern flights. The birds that remain through the winter are those that live on seeds (finches) or those that hunt insects hiding in tree bark (woodpeckers, chickadees, etc.). Cedar waxwings spend their winters here searching for fruit and berries.

But, you might say, robins are around all winter. This is true, but the majority of robins do migrate. Those that stay behind change their behavior and their diet: They become nomadic, spending their days in flocks searching for fruit, such as crabapples, mountain ash berries, juniper berries, winterberries and others. When spring comes, the flocks break up, their diet changes back to arthropods, they’re spotted on lawns again, and we say, “The robins are back.” Our resident birds, those that don’t migrate, are seed eaters, like finches, or larval insect hunters, like woodpeckers.

Q: Could I have seen a big group of pelicans flying over the Minnesota River in Bloomington recently? I’ve never seen them in Minnesota before and was shocked to think they’d be in our state. Is this normal?

A. Yes, it’s quite normal for white pelicans to live and breed in Minnesota in the summer, and to be spotted on migration in autumn. They are among the most graceful birds in the air, wheeling and floating on the wind.

A: This is typical behavior for blue jays, a species that is very fond of peanuts in the shell. We see blue jays around all year, but truth to tell, they’re not the same jays from season to season. Blue jays from farther north move into our area in the fall, just as our summer jays are making a trip southward. So, we always have jays, just not the same jays, and the jays visiting for your peanuts are probably on their way to or from other areas. The fact that you don’t see jays at all during the summer is probably due to the fact that jays become extremely secretive during nesting season, in order to avoid the eyes of predators.

Q: I love everything about sandhill cranes, from their calls to their size to the way they stalk around on the ground, but I don’t want to go all the way to Nebraska to see them in the fall. Any ideas?

A. Sandhill cranes are a joy to watch, either striding through a wetland or flying overhead with their long legs extended. You certainly can get good looks at cranes closer to home. One good spot to see these tall birds into November is the Sherburne National Wildlife Refuge in Zimmerman, Minn. The refuge is a stopover for thousands of cranes as they migrate in the fall. It’s a good idea to visit the refuge’s website before a visit, to learn what trails are closed due to hunting season, etc.

Q: I took a drive in mid-October, and noticed quite a few bluebirds sitting on utility wires out in the countryside. I’ve never seen more than two at once; what was going on?

A: In the fall, Eastern bluebirds tend to gather in flocks before migrating southward. Adult birds are joined by youngsters hatched this summer, leading to groups of a hundred bluebirds or more. Insects make up much of the diet of these beautiful thrushes, so after fattening up in the fall, they take wing for winter homes.

Thumbs down on grackles: “At my house and in my neighborhood (Woodbury) grackles are a problem until late in the fall. I can walk in the neighborhood and see hundreds of them in the trees. A hundred or more of them swoop in and eat everything in my feeders within 15 minutes. I take down the seed feeders and suet for a week or so to discourage them, but when I put the feeders back out, they find them pretty quickly. It’s a pity because I know they are very smart birds and actually very pretty. But it says something when I’d rather have starlings, house sparrows and red-winged blackbirds in my yard.”

More tolerance for grackles: “It disturbs me to see people whom you would think have an appreciation for nature assigning value to some birds while trying to get rid of others. I happen to love watching a grackle stride across a lawn, his head feathers gleaming iridescent green in the sun. Who decides which birds are desirable and what makes them worth more than other birds? For instance, predator birds like eagles and hawks seem to be considered more precious than turkey vultures that eat dead things. Assigning value to certain birds seems to me to be close to valuing some human beings more than others.”