Mute Swans Find Unwelcome Mat Out in New England

As biologist Maynard Vance paddled his canoe through the reeds, a majestic white bird glided toward him, puffing its wings and emitting wheezy whistles and snorts.

“He’s guarding a nest somewhere near here, but it’s well hidden in those cattails,” said Vance, who works for the state Department of Environmental Conservation. “They build their nests on muskrat mounds.”

The bird that engaged Vance in a floating pas de deux was a mute swan, one of three males seen on a state-owned marsh near the Hudson River about 40 miles south of Albany.

To the casual bird-watcher, the elegant swans, pure white except for a black mask and knob over the yellow bill, may be a welcome sight. But to biologists, the birds are bad news.

Two species of swan are native to North America: the trumpeter and the tundra, or whistling, swan. The mute swan, whose neck is more curvy and voice less melodious than the trumpeter and whistler, is a foreigner.

Like the European starling, Norway rat, Eurasian milfoil and gypsy moth, the mute swan is an exotic species with the potential to cause ecological havoc.

The 25-pound birds eat huge quantities of water plants. They aggressively defend a nesting area as large as 10 acres against ducks, geese and canoeists. And their cigar-size droppings befoul beaches and reservoirs.

Wildlife biologists in New York, New England and the Great Lakes states want to curb the growing population of wild mute swans.

Efforts so far have centered on addling, or shaking, swan eggs to kill the developing embryo. (If the eggs were simply broken or removed, the swans would lay more.) In some cases, wildlife agencies have shot swans or trapped them, sending them to zoos or private ponds.

No control method is without controversy. After all, swans have more charm than, say, a lake-choking weed like milfoil.

“They’re pretty marvelous birds,” said Mike Mossman, a research biologist with the Wisconsin Department of Natural Resources. “I can understand people not wanting them to be controlled. But we’ve . . . decided we have to do something before they get out of hand.”

“This is an exotic species, which is displacing native birds like black ducks and mallards in some areas,” said Bryan Swift, a state waterfowl specialist in New York.

Mute swans are indigenous to Russia and Europe, where they have been domesticated by the royal and wealthy and immortalized by the likes of Yeats, Tchaikovsky and Hans Christian Anderson.

The birds were imported to America around the turn of the century to decorate private estates. Captive swans released in southeastern New York around 1910 are said to be the ancestors of nearly all the wild mute swans in the Atlantic flyway, a region stretching from Quebec to Florida.

A separate population of mute swans, descendants of birds released in Michigan, has been growing in the upper Midwest for seven decades.

More than 8,000 mute swans were counted in the Atlantic flyway last January, said Charles Allin, a biologist in the Rhode Island Department of Environmental Management. That’s an increase of nearly 3,000 since 1987.

The birds are found mainly in coastal areas of New York, Connecticut, Rhode Island, New Jersey, Massachusetts and Maryland.

In Connecticut, which counted 1,813 mute swans last winter, animal rights activists have lobbied against the state’s egg-addling plans, first proposed in 1990 and now in legal limbo.