Birders put in long hours catching, banding raptors

Posted: Friday, October 29, 2004

 

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  A pigeon lure is popped to attract a raptor as seen from a window blind Wednesday, Oct. 13, 2004 at the banding site in the Mount Hood National Forest, Ore. (AP Photo/The Bulletin, Melissa

A pigeon lure is popped to attract a raptor as seen from a window blind Wednesday, Oct. 13, 2004 at the banding site in the Mount Hood National Forest, Ore.

(AP Photo/The Bulletin, Melissa

MOUNT HOOD NATIONAL FOREST, Ore. ''Bird!''

The word tripped an alarm for the three men inside the small, camouflaged banding station 6,000 feet atop Bonney Butte, east of Mount Hood.

Chatter about baseball playoffs stopped, and the men followed the incoming raptor's movements through small rectangular holes cut out of the structure's thin, plywood walls.

Keeping his eyes on the elaborate netting system in front of the blind, 52-year-old Dan Sherman began jerking a string in front of him. Outside, a live pigeon was attached to the string by a tiny, hand-stitched leather safety vest. The bird popped into the air and fluttered back to the ground, imitating a wounded bird.

Sherman popped the pigeon up and down several times, but the raptor, a red-tailed hawk, wasn't interested. When it was clear that the hawk wasn't going to stop, the men relaxed and went back to baseball as they waited for the next bird.

Since late August, Sherman, who works for a plumbing company in Portland, and David Roth, 25, a field biologist from New Jersey, have spent eight hours a day trying to capture and band hawks migrating south for the winter.

 

Field biologist David Roth, from New Jersey, holds a Sharp-shinned Hawk that was captured Wednesday, Oct. 13, 2004 at a banding site in the Mount Hood National Forest, Ore.

(AP Photo/The Bulletin, Melissa

Their work is part of an annual raptor counting program run by HawkWatch International, a conservation group based in Salt Lake City.

For a decade, HawkWatch has been counting and banding raptors on Bonney Butte. It is one of 10 counting sites run by HawkWatch in the United States, and one of only five locations where birds are captured and banded.

The data collected will help scientists understand raptor migration and population trends, as well as spot changes in the environment. Raptors, or birds of prey, are good indicators of environmental health, because they feed at the top of the food chain.

''If something is infecting other species, such as rabbits and fish, the raptors are liable to show the effects first,'' said Rick Gerhard, 47, a raptor biologist who runs the Bonney Butte station and trains the HawkWatch volunteers.

Scientists first realized the dangers of DDT by studying captured peregrine falcons and bald eagles, Gerhardt said.

If the weather holds, the project will continue through October.

With a steady, westward wind, eagles, hawks and falcons migrating south tend to fly along a 35-mile-long north-south ridge within sight of Bonney Butte. The butte, located at the southern end of the ridge, is an ideal spot for counting and capturing those birds.

 

Amy Scarpignato, right, HawkWatch International counter and observer, and Lauryn Garza, HawkWatch International on-site educator, look for raptors Wednesday, Oct. 13, 2004 at the HawkWatch International observation site in the Mount Hood National Forest, Ore.

AP Photo/The Bulletin, Melissa J

Four hundred yards north of the banding station, two young field biologists equipped with binoculars and picture guides spend their days counting the migrating raptors as they fly overhead. A third field biologist ushers visitors through the site.

Funding for the counting and banding project comes from a variety of sources including the U.S. Fish and Wildlife Service, the U.S. Forest Service, HawkWatch members and private donors.

Visitors at the banding station can also sponsor birds for anywhere from $35 for a sharp-shinned hawk to $750 for a raptor equipped with a satellite transmitter. The transmitters track a bird's movement for two years.

So far this year, Sherman, Roth and Gerhardt have caught nearly 400 birds, including 215 sharp-shinned hawks, 89 Cooper's hawks, three Merlin falcons, four prairie falcons, 57 red-tailed hawks and one golden eagle, the rarest capture, said Gerhardt.

''(Eagles) have much better eyesight and are that much more wary,'' he said. ''They may see the pigeon and have a hankering to go down, but they notice something that looks wrong. The other hawks, they're such bird eaters that, man, when they see our pigeon or a starling, they tune everything else out and stay focused on that bird.''

Since late August, counters have spotted 3,575 hawks.

While Gerhardt said catching birds is not rocket science his 13-year-old son has been doing it since he was 8 it takes practice and confidence to handle the birds.

To capture birds, Sherman, Roth and Gerhardt set up a labyrinth of nets in a small clearing outside the blind. At any one time, two pigeons and one starling are used to lure birds into the trapping area. The pigeons and starling are attached to strings controlled from inside the blind.

Smaller hawks tend to fly directly into the nets. But with the larger raptors, the banders pull the pigeon toward a spring-loaded net that is released the moment the hawk grabs the pigeon.

The hawks are not allowed to eat the pigeons or starlings, although a few pigeons get hurt or killed each year, said Gerhardt.

''They are lure birds, not bait,'' he said.

Once a raptor is captured, one of the biologists runs out to the net, grabs the bird by its feet with bare hands gloves would desensitize hands and endanger the bird and resets the trap. Inside the blind, the raptor goes head first into a dark soup or coffee can to keep it calm while it gets banded and measured.

Banders check the age, sex and weight of each bird. They also take careful measurements, including the tail, the crop an area below the beak where hawks store food the amount of fat under the wing pit and the muscularity of the keel, or breast.

The process can take anywhere from nine minutes to an hour, depending on the size of the bird, said Gerhardt. Records are sent to HawkWatch's Salt Lake City headquarters.

''If things are really happening, it's really a three-person job,'' said Gerhardt. ''Last week they actually called a visitor down who had experience with this thing and he helped by doing measurements while they kept trapping,'' he said.

While every capture is an adrenaline rush, ultimately, it's a passion that keeps the modestly compensated field biologists and volunteers coming back to the butte each fall.

In the long-term, information yielded by birds counted and banded at Bonney Butte will help biologists map out exactly where the birds are coming from, where they're going as they migrate and what it says about the environment.

''Eventually, we will detect whatever changes there are,'' said Gerhardt.



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