Leading the way back to the wild Swans: Wildlife experts hoping to restore trumpeter swans to the Chesapeake Bay are trying to teach captive-bred birds to migrate to the bay's wintering grounds.

December 19, 1997|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

WARRENTON, Va. -- Flapping furiously to catch up with the ungainly ultralight airplane they regard as their mother, three sleek white trumpeter swans rose from a frosty hayfield at sunrise yesterday en route to the Chesapeake Bay.

Yo Yo, Isabelle and Sid soon fell into formation off the right wingtip of the noisy aircraft. Together, the odd flock circled the field twice, wheeled gradually to the east and disappeared over treetops.

"They're in the air. They're moving in the direction we want them to. I'd say that's pretty close to perfect," said Bob Ferris, director of species conservation for the Defenders of Wildlife.

Ferris, together with Dr. William Sladen of the Environmental Studies center at Airlie, Va., hope to restore the trumpeters to the bay, where they have been absent for almost 200 years.

With flights like yesterday's, they hope to teach captive-bred birds to migrate to the bay's wintering grounds -- much as their wild ancestors did before hunting and habitat destruction in the 18th and 19th centuries drove them close to extinction in the lower 48 states.

After an overnight layover on the Patuxent River, at Magruders Ferry near Aquasco in Prince George's County, the unlikely squadron was poised today for the final leg of its journey. Scientists hoped to lead them across the Chesapeake to Lakes Cove on the Honga River in Dorchester County.

The 103-mile migration from Virginia to Dorchester County is intended to prove the ultralight technique will work with swans, as it has with geese -- a scientific breakthrough that was the subject of fictional treatment in the 1995 movie, "Fly Away Home."

The exercise also is meant to teach the trumpeters to move in the fall from the freshwater ponds of Airlie, where they were born, to wintering grounds in Dorchester's open tidewater marshes.

If it works, the swans will return to Airlie in the spring. And next year, if the proper permits are secured, Ferris and Sladen hope to raise 20 to 30 trumpeters at Airlie for the next step in their restoration effort.

Once they've learned to fly with ultralights, the swans will be trucked to the Iroquois National Wildlife refuge in upstate New York. From there, they will be led by the aircraft down the East Coast flyway to the Chesapeake, re-learning the ancient migratory route of their ancestors.

"We've made such a mess of our natural world," Sladen said. "We've extirpated so many species that I think if we have a chance, and a new method to do this, we should do the best we can to restore the natural world."

Sixty miles southwest of Washington, the Airlie center is a 3,000-acre conference center. Its Environmental Studies Division works to preserve wildlife habitat, especially wetlands to attract migratory water fowl.

It is here that Sladen -- a polar explorer and professor emeritus at the Johns Hopkins University with degrees in medicine and zoology -- has established a flock of about 160 swans of eight varieties.

Aside from the three females that made the flight to Maryland yesterday, a male, Herbie -- not quite mature enough to go so far by air, was being transported to Dorchester by truck. The others remained behind.

Trumpeters are the largest of North America's water fowl, weighing up to 40 pounds fully grown. Once common from Alaska to Florida, the birds began their decline as soon as European colonization began.

Wiped out

Hunted relentlessly, they were wiped out on the eastern seaboard by the mid-19th century. By 1938, only 69 remained in the lower 48 states. In the Chesapeake, only the tundra swans return now to winter, Sladen said. They number about 25,000.

In 1962, two nonnative mute swans with clipped wings escaped from a private pond into the Chesapeake. Their nonmigrating descendants now total about 2,500, and many naturalists regard them as a serious competitor to the bay's wintering tundra swans.

Efforts to restore the trumpeter swans began with birds from surviving flocks in Alaska and Canada. They have been reintroduced to the wild in Minnesota, South Dakota, Wisconsin and the upper Midwest and are making comeback. A 1990 survey found 15,630 in the wild.

But biologists continue to worry that the reintroduced and relocated birds have not learned to migrate in winter, leaving them vulnerable to the disease, predators, harsh weather and the habitat destruction.

Sladen's dream has been to re-establish migrating trumpeters along the continent's eastern flyway and in particular to the Chesapeake. He hopes that the "imprinting" techniques developed for geese by Austrian scientist Konrad Lorenz may hold the key.

'Mother'

Lorenz discovered that certain birds, when they hatch, adopt the first moving object they see as their "mother."

In 1988, a Canadian aviator named Bill Lishman used that to imprint a clutch of Canada geese on himself and his ultralight airplane.

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