To barred owls, a tree's a tree

Article Date: 2008-01-04   Source: http://seattletimes.nwsource.com   Comments: 1

By Michael Milstein

Charlotte, North Carolina, U.S.A. - Pacing a suburban sidewalk, Cori Cauble rotates an antenna in her hand, listening for telltale beeps. A well-dressed man crossing the street glances at her, lifts a cellphone from his ear and asks, ''The owls?''

''We're looking for them,'' says Cauble, a wildlife researcher from the University of North Carolina, Charlotte (UNCC).

The neighborhoods of Charlotte, lined with graceful houses and arching trees, are home to a booming population of hundreds of barred owls — adaptable birds as happy in one of the largest cities in the South as in an old-growth forest.

Barred owls have provoked controversy: Federal agencies recently proposed shooting them in the Pacific Northwest, where barred owls have invaded old-growth forests that were once the exclusive haunt of the closely related, but endangered, spotted owl. In the past decade, the number of spotted owls in Washington has declined nearly 7 percent a year — in part because the bigger, more aggressive barred owl expanded its range in the state and began driving out its threatened cousin.

But barred owls are also interesting and engaging, said Bob Sallinger, conservation director at the Audubon Society of Portland.

"They're a wonderful bird — all the controversy and politics and biology aside," Sallinger said. "That's what makes all this so interesting."

Spotted owls are particular about where they live and what they eat; barred owls aren't. They find all the forest they need in suburban backyards and eat almost anything that moves — snakes, bats, opossums. Charlotte researchers call one owl-nest box the sushi box because the owls living in it feast on so many fish.

"The city, as far as they're concerned, is the forest," said Rob Bierregaard, a UNCC ecologist and ornithologist leading a six-year-old study of local barred owls that is one of the most extensive owl studies undertaken. "We found one sleeping over a sidewalk with people walking 6 feet under it all day long."

At least from a human point of view, the owls are generally puppy-dog friendly, he said, except when a biologist like Bierregaard is climbing a tree to band their young — a situation in which he wears a lacrosse helmet as defense against the divebombing parents.

He's a kind of pied piper of owls, walking through neighborhoods with a boombox playing owl calls — and known locally as "the owl man."

The Charlotte owls themselves are popular local celebrities.

Bierregaard, Cauble and other UNCC researchers mounted nest boxes in parks and backyards. Tiny infrared cameras in the boxes let the scientists watch what the owls are doing and eating, and provide a public window into the lives of the birds.

The researchers record video from the cameras, and while they're at it they pipe the video to televisions in living rooms of nearby homes.

"When he first hooked up the video, I stayed up all night because I didn't want to miss anything," said Frances Evans, who has grown especially fond of the owls nesting in a box attached to a willow oak towering over her back lawn. The camera gives her a clear view of the owl chicks as they wait for their mother to return with a meal.

It's a point of pride that an owl was once fitted with a radio transmitter in her kitchen. She and her husband, Don, have a friendly competition with neighbors over who has the most owl-friendly yard.

Nesting season has gotten as popular as football season as everyone gathers round their TV for owl-watching parties.

"Other people hear about it and say, 'Can we come too?' I say, 'Sure,' " she said, showing off photos of herself holding the owl fledglings when researchers visited to fit them with tags. "It's so exciting — you'd think they were my own children. Then they flew away, and I felt like an empty-nester all over again."

Barred owls are native to East Coast states but appear to be multiplying, especially in urban areas where trees are growing large enough to simulate the big trees they prefer in the wild. No one is sure why they spread westward. Some suggest it is a natural expansion, though one theory suggests they hopscotched through trees that grew up in the Midwest as settlers began extinguishing wildfires that once burned such trees away.

The generalist nature of barred owls, compared with the specialization of spotted owls, gives them a more secure foothold regardless of habitat.

Barred owls seem to be populating Charlotte much more densely than they do wild forests — sometimes nesting no more than 300 yards apart, Bierregaard's team has found. The city appears to be saturated with owls; when owls die, they are very quickly replaced and Bierregaard has found young owls trying to nest even in small trees he'd expect them to pass up.

"I can't go anywhere where I can't find them," he said.

He suspects they will populate the expanding suburbs of Charlotte in even greater numbers as trees there mature, developing the cavities and large branches the owls like.

The city owls feed heavily on small birds, perhaps drawn to backyard feeders, but the owls themselves have no real predators, the researchers say. The most frequent cause of death for owls fitted with radio transmitters is getting hit by cars when they're flying after prey.

The infrared cameras have given researchers a more complete picture of the birds' lives — revealing types of prey they might not recognize through traditional methods such as checking pellets of undigested food, Cauble said.

"We're seeing a lot of snakes in the cameras," she said. "That's something you wouldn't necessarily see in the pellets."

It has also countered common expectations for the owls.

"If you read the textbooks, they say the owls stay away from people and development," Cauble said. "Obviously, they don't stay away from here."

Related Articles:
2008-11-25 - Environmental groups go to court over the spotted owl by Michael Milstein - Washington, DC, U.S.A.
2008-05-17 - Plan for saving spotted owl recommends maintaining older forests west of the Cascades by Michael Milstein - Oregon, U.S.A.
2008-01-25 - The owls among us by Bruce Henderson - Charlotte, North Carolina, U.S.A.
2007-10-16 - Ecologists discover city is 'uber-forest' for big owls by James Hathaway - Charlotte, North Carolina, U.S.A.
2007-07-29 - So much for saving the spotted owl by Michael Milstein - Oregon, U.S.A.
2004-05-31 - A no-holds-barred owl war by Michael Milstein - Oregon, U.S.A.

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On 2009-01-29, cassie nims from lakeville michigan wrote: "wow the barred owl is so cool and well i have one living right bye my house its so cool"

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