Q On a recent evening, I visited a friend who lives in Minneapolis near the Mississippi River. When I got out of my car, I could hear a distinct droning, raspy sound that seemed to be coming from the treetops. I asked my friend what that sound was and she said she thought it was a nightjar. Could that be right?
A Yes, that could be right. It's interesting your friend should mention nightjars. Not many people identify birds by family.
In Minnesota we have two breeding species of nightjar, the whippoorwill and the common nighthawk. Because you'd know the whippoorwill's distinctive call, we presume you suspect the common nighthawk to be your noisemaker.
The common nighthawk has a call that is commonly heard in summer. It's a nasal "peent" -- a raspy, staccato call about a half-second in duration, given in a rhythm of perhaps 20 calls a minute when they are most active, which is just after sunset.
However, from your description, it could also be a cicada. Cicadas are well-known for making a long, droning, buzzing call from the tops of trees. There are two species common to Minnesota, each with its own song. Their songs are most commonly heard in the hottest part of the day in late summer. The song of the dog-day cicada lasts about a minute and somewhat resembles a chain saw. The Say's pruinose cicada has a variable call, which is described as a "zee-oo," repeated for 20 seconds at a time.
Silent wrens Q We've had wrens nesting in our yard for years. This year, one pair nested in the front yard in the spring. Later, another pair nested in the back yard. The pair in the back yard never sang. Any idea why?
A It's possible that the birds weren't able to nest successfully in your front yard because of predation or competition from another pair of wrens. They might have tried to nest again, building a second nest in your back yard. That might explain why they were quiet: Having already paired up, they wouldn't need to make courting calls. In addition, they might have been trying not to draw attention to themselves and their second nest.
Red-headed sparrows Q I have seen a bird in my St. Paul yard that looks like a sparrow but has a distinctly red head. What could it be?