If you heard a bird calling in a “descending tremolo” recently, says Francie Krawcke, you were probably eavesdropping on a screech owl’s courtship.
“They call when it’s dark during mating season to say ‘This is my space! Stay out!’,” explains Krawcke, the raptor expert at the Leslie Science and Nature Center. And no, “they don’t actually screech,” she adds. The whistle is “not very loud, but if it was sitting in a tree above your house, you can really hear it.”
And, during mating season in March, you can hear it just about everywhere. “Screech owls are all over the county,” says Michael Kielb, professor of biology at EMU and co-author of The Birds of Washtenaw County. “Every little woodlot around the county has a pair. If you were to draw a quarter-mile circle anywhere in the county, somewhere in that circle, you would have a pair of screech owls.”
Asked how long they mate for, Kielb replies, “about thirty seconds”–then laughs. “It’s guesswork,” he says more seriously. “They usually live two to four years, but they can go up to seven, and they stay together for the life of the partner–though I’d hedge on that because you can never really tell with birds.”
Eggs laid in March typically hatch in April, says Kielb. The young begin to leave the nest in May, “and by June-July, we’ll see family groups.”
What do they eat? “Mostly mice, shrews, and voles,” says Kielb. What eats them? “Bigger owls like barn owls or great horned owls, also weasels and feral cats.”
County naturalist Faye Stoner leads “owl walks” for people who’d like to see–or at least hear–the small, night-flying predators. “We go out at dusk, try to be quiet, and use a tape recoding of screech owls to call real screech owls,” she says.
On one outing, she recalls with excitement, her group “saw a silhouette of an owl who had a mouse in his talons. We even flashed lights at him, and he stayed put. That doesn’t always happen. They can be really skittish.”