House wrens can be fierce protectors of nests

Q: I didn't know what was going on, but I heard a ruckus outside and found a pair of house wrens harassing a young gray squirrel on my deck. The plucky birds had chased it all the way to the ground from a tree. Could they still have been nesting?

A: Yes, even though this took place in late summer, those wrens might have been feeling the need to defend a nest. House wrens usually raise two broods of youngsters during the summer, so these fierce little birds probably were trying to drive off a possible intruder.

Who goes first?

Q: When do the first migratory birds leave our area in the fall?

A: Let's focus on the birds we might see in our backyards and parks (shorebirds and some others leave as early as July). The major factor that determines when birds depart on fall migration is how far they need to travel to reach their winter homes. Long-distance migrants, birds that go as far as Central and South America, are the first to leave. For instance, male ruby-throated hummingbirds head out as early as mid-August (females and juveniles stay for another month). Baltimore orioles, scarlet tanagers, Eastern kingbirds and barn swallows all start to depart in August, as do many hawks and osprey. Short-distance migrants, like robins and bluebirds, which fly only several hundred miles southward, might not head out before late September or early October.

Birds and fireworks

Q: Are birds OK with fireworks?

Many municipalities are switching to laser light shows or drone displays, both of which cause much less distress to birds.

On the wire

Q: I was driving down a rural road recently and noticed hundreds of birds perched on the utility wires along the road. What were they and what were they doing?

A: I'm betting these were swallows, including bank, tree and rough-winged swallows, and purple martins. These insect-eating birds gather in large flocks in the fall before migrating.

Late bloomers

A: Yes, goldfinches settle down to nest just as some other birds are preparing to leave on migration. Nesting season for these little yellow finches coincides with the maturing of thistles, a source of food and nest-building material. Goldfinches use thistle down to line their small cup nests, and they dine on thistle seed and feed it to their young. Young birds leave the nest about four weeks after hatching, so they have to hurry up and develop life skills before the onset of winter.

Lack of vultures

Q: Why don't I see turkey vultures in winter?

A: These large raptors, "nature's cleanup crew," are migratory and leave our region by early October. You've probably seen these birds soaring gracefully overhead or on the ground, feeding on roadkill or other carrion.

Eagles: stay or go?

A: She is, but then, you are, too. Bald eagles do begin moving southward in the fall, but some remain all winter along open water in the metro area: A good place to view bald eagles in winter is in the corridor from Red Wing to Wabasha, where a large number of eagles overwinter in the open water created by the Chippewa River flowing into the Mississippi. If you're down that way, stop at the National Eagle Center in Wabasha (there is an admission fee), for a fascinating, in-depth look at our national bird.

Note to readers: Duluth's Hawk Ridge is known worldwide for the spectacular migration of raptors that pass over and around the ridge overlooking Lake Superior. Everyone is welcome to spend time at the ridge and enjoy the fabulous scenery; there's no charge to listen to naturalists discuss raptor migration. September and October are the best months to visit. Learn more at www.hawkridge.org/plan-your-visit/visitors-guide/.

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.