Liam Revell was on his standard six-mile run in Old West Durham around dusk last week when he saw something flapping above his head. A heavy shadow closed in above him. He felt a weight and something sharp on his head.

"I thought it was bat," said Revell, 29, a post-doctorial fellow at Duke University. "I probably shouted, swatted at it."

The culprit, which turned out to be a barred owl, released Revell and flapped up to the power lines above Hale Street.

"It was probably only attached to me for a split second," he said, adding that it didn't draw blood but stung a bit. Revell got a camera from his home around the corner and returned to take photos of the owl, which was still perched on the power lines.

"The guy who lives right in front of where the owl had landed came out of his house," Revell said. "He told me he had heard of three previous similar incidents. His girlfriend had been swooped at."

Revell is among a handful of residents in the Old West Durham and the adjacent Watts Hospital-Hillandale neighborhoods who have reported similar encounters since August with the large, brown-eyed owls. No injuries have been reported beyond minor scratches, according to interviews.

On Sept. 29, Joel Sadler was jogging about 6:30 a.m. in the same area and he noticed a strange shadow getting bigger and bigger.

"I panicked, I just started ducking away from it and swinging over my head," said Sadler, a 28-year-old marketing director.

The owl flew up into a tree and just looked at him, he said.

"And that was it," Sadler said. "I kept running and I never saw it again."

Beyond being startled, city residents and victims of the dive-bombing birds don't appear to be living in fear of owl attacks.

"They don't carry any serious diseases," said Revell, who is studying evolutionary biology. "One of the great features of Durham is it has all these green spaces. We can have this interaction in the urban center and that is so rare."

N.C. Wildlife Commission biologist George Strader said he occasionally receives phone calls about owls from residents who are concerned about their pets.

"I can't say I have ever known of a confirmed case where an owl took a small pet," but that doesn't mean it hasn't happened, he said. In general, owls feed on small rodents such as mice, squirrels, and rabbits. Strader advised, however, that it might be a good idea to walk small pets on a short leash and keep them inside at night.

A half-grown rabbit is generally the biggest animal the barred owl can catch, said Rob Bierregaard, a UNC-Charlotte biology professor who has been studying the raptors for 10 years.

"They couldn't really take a full-grown one, that would be a lot," he said. "As a rule they have pretty small feet."

Such encounters with the birds in late August, September, and October are not necessarily unusual. A Rock Hill, S.C., walking trail was reportedly closed temporarily in late September after two people reported being attacked by an owl. In September 2006, Chapel Hill joggers reported similar occurrences.

Experts, however, can't pinpoint why the owls would be so territorial in the late summer, early fall months.

"That is one thing that perplexes even a barred owl specialist," Bierregaard said.

Owlets have usually left the nest by July, and adults don't start thinking about nesting until January, he said.

Bierregaard, and other experts, did say that the owls aren't likely mistaking people for prey because they realize they can't catch something so large.

Mathias Engelmann, rehabilitation coordinator for the nonprofit Carolina Raptor Center, said in his 26 years working for the agency he knows of only one "extreme" instance in which a homeowner asked that an owl be removed because he feared physical injury.

Engelmann and others recommended joggers avoid the areas where others have encountered the aggressive owls, and consider wearing hats.

"And don't wear a fur-covered hat," Bierregaard said.