WALNUT CREEK — Twenty woodpeckers from the retirement community of Rossmoor that are in the crosshairs of a federal hunter have been captured and trucked to a federal research center in Colorado to test whether bird sounds can be used to scare them into not damaging homes and buildings.

Workers with a branch of the U.S. Department of Agriculture that specializes in human-wildlife conflicts captured the birds last month. They trucked the birds overnight to the National Wildlife Research Center in Fort Collins to test a device that mimics hawk and other bird calls.

Federal officials said the tests could break new ground in protecting buildings without killing the acorn woodpeckers that peck into them.

Skeptics from the Audubon Society said they wonder if the capture of the birds was just a politically easier way of removing the birds from Rossmoor, where plans to shoot them spurred a public outcry.

"I feel they blindsided us and outwitted us, and found another way to get what they wanted: removal of the woodpeckers from Rossmoor," said Diana Granados, a member of the Audubon Society's Mount Diablo chapter. "Maybe their research will produce an effective tool to scare woodpeckers, but in general, these scaring devices work a little while at first and then the birds figure out they're fake."

A federal spokesman said the birds were captured for science, not just to get them out of Rossmoor.

"We want to find out if this sound device scares away the acorn woodpeckers," said Gail Keirn, a spokeswoman for the National Wildlife Research Center. The facility is operated by the USDA's Animal and Plant Health Inspection Service.

Under a state permit to capture the animals, the 20 woodpeckers must be put to sleep rather than released back into the wild after the research is done, she said. The life of the birds could be extended if the birds can be used in other tests, she added.

The tests will be done over several months in an enclosed area large enough for the birds to fly in. Large utility poles will be fitted with the scary sound devices to find out if the woodpeckers will stay away, Keirn said.

Last year, the U.S. Fish and Wildlife Service granted permits to two Rossmoor homeowners associations to call in a federal hunter to shoot as many as 50 acorn woodpeckers that were pecking into the sides of buildings.

At least seven of the birds were shot before a public outcry resulted in at least a temporary stop to the shootings. The permit to kill the birds expired Saturday.

Reach Denis Cuff at 925-943-8267 or dcuff@bayareanewsgroup.com.