Scientists say their effort to teach young trumpeter swans to migrate was successful enough to move forward this year with plans to re-establish North America's largest waterfowl in the Bay region.
Hunters had wiped out the swans in this area nearly two centuries ago. But scientists last year conducted an experiment that taught three young swans to "migrate" 103 miles from Virginia to Maryland's Eastern Shore behind an ultralight aircraft "mother."
This spring, they waited to see whether the swans would return on their own.
"All three initiated the migration," said Gavin Shire, a biologist and pilot scientist with Environmental Studies at Airlie, outside Warrenton, VA, which is overseeing the project. "One of them made it all the way back."
But the news is better than that, Shire said. One swan got as far back as the Patuxent River when someone, thinking the swan was lost, captured the bird and took it home to report the find. During the night, a dog attacked the swan. Although it survived, it had to be driven back to Airlie for treatment.
"That bird, we felt, would have made it all the way back, but unfortunately didn't get the chance," Shire said.
Another bird made it halfway home, then turned around and went back to the Eastern Shore. Scientists planned to wait until late May to see whether she would complete the migration; if not, they anticipated capturing the bird and returning it to Airlie.
Because one bird completed the return migration - and a second bird likely would have - Shire said the experiment was a success. "We wanted to show the birds can find their way back on their own," he said.
In the wild, Shire noted, trumpeter swans often make their return migration with their parents, flying in a long direct path. Those without parents make the flight in a series of "short hops," taking a less direct route. Therefore, Shire said, the three swans exhibited behavior similar to orphan birds in the wild.
Project scientists are now moving forward with plans to establish a permanent migrating population between New York and the Eastern Shore.
More young swans are being reared at Airlie, and later this year they will be trucked to a site in New York that will become their breeding grounds in future years. Once there, they will be taught to fly behind an ultralight and - if all goes well - they will be lead on a migration to their Eastern Shore wintering grounds this fall.
After that, it is hoped they will return to New York on their own next spring, establishing a permanent migration route. The project uses the ultralight technique developed a decade ago to teach
Canada geese to migrate - an effort popularized in the movie, "Fly Away Home."
Swans learn migration routes from their parents. The only way to have taught these birds to migrate was to provide them with a surrogate parent - the ultralight aircraft - to show the way.
Migration is considered important because birds take advantage of food supplies in different regions at different times of the year. If the birds do not learn to migrate, their year-round presence could result in their becoming a nuisance species, as is the case of the large flocks of "resident" Canada geese that overrun parks, fields and golf courses in the region.
Trumpeter swans once lived in nearly all of North America. About 100,000 wintered in the Chesapeake Bay area about 200 years ago, but they were an early victim of European settlement. By 1932, overhunting had left only 69 trumpeters in the lower 48 states.
There are now about 19,000 trumpeter swans in North America, 16,000 of them in a migratory flock that breeds in Alaska and winters in the Pacific Northwest. The remaining 3,000 are in a few small, non-migratory flocks in Iowa and around the Great Lakes.
The birds, white with a black beak, weigh up to 30 pounds, have an 8-foot wing span and can stand 4-5 feet tall. They have a long, convoluted trachea that produces the resonant trumpeting sound.
People can learn more about the project at the Environmental Studies web site: www.iapm.org.
Anyone wishing to support the privately financed venture may make a pledge by calling 888-2-MIGRATE.