MINNEAPOLIS -- It's been a tough winter for owls in parts of North America, and the evidence is turning up on roadsides, at bird feeders and at a wildlife rehabilitation center in Minnesota.

The dead, injured and sick owls are symptoms of what ornithologists call an "irruption," a cyclical phenomenon in which owls that normally winter in northern Canada head south in search of food when mice, voles and lemmings are in short supply or snow cover makes it hard to hunt for them. Other irruptions have been reported recently in New England, southern Ontario and Quebec, and parts of British Columbia.

This year, northern Minnesota is seeing much of the action, mostly tiny boreal owls.

"They're excruciatingly cute," said Geoff LeBaron, director of the Christmas Bird Count program at the National Audubon Society.

The prime owl habitat of the Sax-Zim Bog, 45 miles northwest of Duluth, has an annual birding festival in February. Boreal owls are tough to see because they're small and don't usually come out in daylight. They sit very still when they perch.

Irruptions tend to involve less-experienced young owls that don't know about dangers from humans, like cars, and are more likely to end up as roadkill. -- AP

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