State devising plans to control local population of mute swans

Large birds damage environment, DNR says

May 11, 2002|By Heather Dewar | Heather Dewar,SUN STAFF

A state plan for controlling beautiful but destructive mute swans calls for creating "exclusion zones" where the birds would be eliminated by several means, including lethal injection or shooting, officials said.

The plan, due to be made public in about two weeks, does not call for getting rid of the birds entirely. It would keep them out of sensitive areas -- places where the swans are eating all the underwater grasses, behaving aggressively toward people, or trampling nests of increasingly rare native birds such as black ducks and least terns.

The state also would continue efforts to prevent swan eggs from hatching by shaking them or coating them with corn oil, which prevents oxygen from reaching the embryos. Under a permit from the U.S. Fish and Wildlife Service, state biologists and volunteers have "addled" eggs in about 125 nests this spring, wildlife managers say.

Under the new plan, wildlife managers could kill swans only where they judge that nonlethal means won't work, Paul Peditto, director of the Department of Natural Resources' wildlife and heritage division, said yesterday. The public would still be forbidden from hunting the birds, which are protected by federal law.

The intent is to keep the swans' population "at a level that's compatible with native wildlife and habitat," said Larry Hindman, DNR's waterfowl program leader.

Opponents, including Trappe resident Patrick Hornberger, say their encounters with mute swans don't jibe with DNR biologists' claims that the birds are greedy, aggressive and harmful to bay life.

Each year, one to four pairs of swans nest on the creek near his home, and they do no harm, Hornberger said. "It's almost a domestic bird. Is it really the nuisance they say it is? They haven't convinced me."

Others disagree.

"Something's got to be done, and I'm sorry it has to be that way," said Bobbie Seger, who lives on Waverly Island near St. Michaels, within sight of two mute swan nests. "I don't have a soft spot in my heart for these birds, even though I recognize their beauty."

DNR staffers acknowledge that their plan -- which is being discussed internally and may be modified -- will trigger debate.

"It's going to be an issue that polarizes people," Hindman said. "There are some people that don't want anything done to them, and we recognize that. There are other people who consider them a nuisance and want them removed."

The orange-beaked birds, natives of Asia, were imported to Europe for their beauty and brought to America in the 1800s. They were largely kept captive at stately homes, but in 1965, five escaped from a Talbot County estate during a storm.

Since then, the number in Maryland has swelled to an estimated 4,000, about one-third of the entire Atlantic Coast population, Hindman said. Mute swans are long-lived and prolific -- a female may produce up to 30 offspring in her 20-year life span, he said.

Unlike the black-beaked tundra swans that visit the Chesapeake Bay in winter, mute swans live here year-round. In spring and summer, when underwater grasses are growing and setting seeds, each 18- to 25-pound mute swan eats 6 to 8 pounds of grass a day, said Hindman. He estimates the birds are consuming about 9 million pounds a year.

That's a big problem for efforts to restore the bay, which depends on a healthy population of underwater grasses to provide essential shelter for crabs and fish and replenish oxygen supplies.

Grasses now cover about 70,000 acres of bay bottom, far less than before the Chesapeake shoreline sprouted cities and farms, and the bay states have set a goal of restoring grasses to about 44,000 more acres.

The exclusion zones have not been drawn. But Peditto said they probably would include areas where the swan population is dense, such as Talbot County and the Chester River on the Eastern Shore, and the Severn and South rivers in Anne Arundel County.

Property owners who want to keep swans on their land could get DNR permits. But they would have to take measures to prevent the swans from escaping, such as clipping their wings, Peditto said.

"Our goal is not going to be to eradicate all mute swans from the Chesapeake Bay," he said. "There will be an opportunity to support some swan populations in some areas."

The state plan closely tracks recommendations of a task force that studied the issue for two years, Peditto said. It would need the approval of the U.S. Fish and Wildlife Service.

Of the 13 states that have large populations of the birds, several -- including Virginia, Delaware, Vermont, Michigan and Wisconsin -- allow their killing, either by wildlife officers or during a hunting season, Hindman said.

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