Owl of a sudden, long-eared owls are everywhere

February 10, 2017, 12 p.m.
long-eared owl, Asio otus
Photo: Piotr Krzeslak/Shutterstock

Long-eared owls don't actually have long ears. They're named after tall, feathery tufts on their heads that look like ears. Their real ones are hidden under facial feathers, and for many North American long-eared owls, those ears must have been burning lately.

Normally secretive birds, long-eared owls have become a sensation this winter around Chicago, where they've dazzled people by suddenly appearing in unusually large numbers. This is known as an irruption, the technical name for any abrupt surge in a bird population, especially outside its typical haunts. It's unclear where exactly all these long-eared owls came from, but the species is known to breed across a northern swath of the U.S. from Maine to California, plus much of Canada.

Long-eared owls are native to Eurasia and North Africa as well as North America. They live year-round in many regions, but some also escape the northernmost parts of their breeding range during winter, moving south into (slightly) warmer habitats.

long-eared owl distribution map Distribution of the long-eared owl (Asio otus) and the breeding range of its four subspecies. (Map: Wikimedia Commons)

"Owls are irruptive migrants, meaning that where they show up and how many individuals are spotted during the winter can be somewhat unpredictable," Audubon Great Lakes' Stephanie Beilke tells the Chicago Tribune. "Not much is currently known about what triggers an irruption, but it could be related to food availability and changes in population sizes."

Long-eared owls eat mostly rodents and other small mammals, according to the Cornell Lab or Ornithology, including voles, a variety of mice, kangaroo rats, shrews, pocket gophers, and young rats or rabbits. Because many of these animals undergo boom-and-bust population cycles, an owl irruption could occur when food supplies plummet in the birds' normal habitat, forcing them to explore less optimal places, like a metro area of nearly 10 million people. It could also be the opposite, however, with plentiful food fueling an especially productive breeding season, resulting in more owls — and thus more visibility for these rarely seen raptors.

Like many owls, long-eareds hunt at night, coasting quietly over fields and open woods just a few feet off the ground. They find prey by sight or sound, then swoop to grab it with their talons. They prefer habitats with a mix of forest and grassland, since they need places to hunt by night and roost by day. During winter, groups of these owls often roost communally in groves of conifers, willows, mesquites or other trees, according to the National Audubon Society, where their plumage offers excellent camouflage.

"These birds are resting and want to remain hidden during the day," Beilke says. "If you are lucky enough to find roosting long-eared owls, try to keep your distance, and refrain from disturbing the birds."

The long-eared owl isn't considered a threatened species, and tens of thousands reportedly exist around the world. But as the Audubon Society explains, suitable climate for wintering long-eared owls is moving north due to climate change. "This northward shift translates into a 73 percent loss of current winter range," it notes, "giving the species an onerous journey for the future."

When winter ends, long-eared owls shift from communal roosting to breeding and nesting. Spring and summer are good times to listen for their calls, which range from whistles, whines, shrieks and meows to low, soft hoots like this: