BY ROBERT PREER, GLOBE CORRESPONDENT, Summer 2001
Proliferation of swans spurs concerns
When the first mute swans appeared on Straits Pond on the Hull-Cohasset border, residents cheered the arrival of the graceful white birds with S-shaped necks and regal bearing. Then, more swans came. In 1999, there were 36 on the pond, which is just inland from the Atlantic Ocean. The following year; 57. This year’s count- 77.
The proliferation of the huge birds – the first or second largest flying animal in the world (some ornithologists consider the trumpeter swan larger) – is alarming residents on the shores of the 92-acre pond, which has suffered from years of septic pollution and stormwater runoff. While extension of municipal sewers in Hull and Cohasset has buoyed hopes for the pond’s recovery, many residents now view the swans as a new threat.
“They are a very beautiful problem,” said Lawry Reid of Hull, president of the Straits Pond Association. “We are certainty enjoying the swans, but they are exacerbating the problems we already have.” Adult swans weigh between 20 and 40 pounds, and each day consume 10 pounds of plant life. The nutrients in the swans’ excrement, which is about the size and shape of that produced by dogs, are feeding an overgrowth of aquatic plants and algae. “We have too much plant growth,” said Reid. This is not an ecologically healthy pond.”
From Virginia to Boston’s North Shore and in scattered lakes and ponds in the Northeast and Midwest, concern is mounting about growing numbers of mute swans. The birds, introduced to this country from Europe in the late 1800s as captives, have been expanding significantly in the wild for roughly the past 20 years.
In addition to contributing to pollution, swans are seen by some biologists as a threat to native species, especially certain kinds of ducks, which cannot compete with swans for food and nesting areas. Also, swans can be aggressive and have attacked humans and pets. The first mute swans in America were brought to adorn parks and estates, in the same way European monarchs kept swans as royal birds on palace grounds.
The wings of captive birds were clipped to keep them from flying. Some swans, probably offspring of the captives, escaped, and by the 1920s, a wild population had been established on Long Island. Swans then expanded up and down the Atlantic coast.
In Massachusetts, the largest concentration is in the southeastern part of the state, especially the South Shore and Martha’s Vineyard. In recent years, the population has expanded inland and to the North Shore, according to the state Division of Fisheries and Wildlife. In the south suburbs, swans are found on dozens of ponds, rivers, and harbors, both fresh and saltwater.
Musquashicut Pond in Scituate and the freshwater Billington Sea in Plymouth have large numbers of swans. They also have been seen in Scituate Harbor and at Long Pond and Jenney Pond in Plymouth, D.W. Field Park in Brockton, Black’s Creek in Quincy’s Merrymount Park, Island Grove Pond in Abington, and Ponkapoag Pond in Canton in the Blue Hills Reservation.
The Massachusetts Division of Fisheries and Wildlife has been tracking the state’s mute swan population since 1985. In that period, the numbers have increased from 400 to roughly 900 today. The Massachusetts Audubon Society’s less scientific annual Christmas bird count does not show a significant increase in the swan population. From 1982 to 1999, the number of swans counted by Audubon volunteers has been steady at around 600.
Mute swans do not migrate but in winter often move about in search of food as ponds freeze. Although ungainly on takeoff and landing, swans are strong fliers, and can reach 40 miles per hour.
Among biologists and wildlife management officials there is widespread – though not unanimous – agreement that swans are a problem in the state. Swans are viewed as an invasive, nonnative species, like the European starling or English sparrow. At their size, swans have few predators. Snapping turtles, dogs, and coyotes are the only animals locally that pose much of a threat.
“I’m very concerned about the range expansion of the bird,” said H Heusmann, waterfowl biologist for Fisheries and Wildlife. “The damage they do is incremental. You may not notice it, but it will buildup.” Linda Coca, natural history information coordinator for the Massachusetts Audubon Society, said, “There isn’t a biologist in the state who is happy they are here. They are not a good thing.” Less alarmed about the expansion of the mute swan population is David Clapp, director of the Massachusetts Audubon Society’s regional office in Marshfield. He said that while there are more swans in the state now, their numbers are not exploding, nor are they causing huge problems.
Clapp said that while swans can compete with native breeding ducks for habitat, “frankly we don’t have many native breeding ducks in Massachusetts.” More serious invasive species are plants that are choking local ponds, according to Clapp. “There are bigger problems to put your energies into.”
What is dear is that the public loves swans. Few sights in nature are more appealing than a mated pair of swans floating on the water with the cygnets or young trailing the mother. The flight of the swan also is spectacular. “When they start to flap their wings to fly, it is an amazing sound,” Reid said. The arrival of a pair of captive swans on the Boston Public Garden is celebrated as a rite of spring. In response to requests from the public, Boston park officials this year agreed to place a pair of swans on Jamaica Pond. The swans at the Public Garden and on Jamaica Pond are same sex birds, raised on a farm, and are young birds, which are less aggressive than older ones.
Although hand feeding of swans is a common practice in parks, humans are wise to keep their distance. Swans can inflict severe cuts with their beaks. In the water, they use their wings to beat and drown anything they perceive as an enemy. There are two recorded cases of humans being killed by swans. In 1982, a fisherman in Indiana died when a swan apparently capsized his boat and drowned him. Although accounts are sketchy, a child in Massachusetts was reported killed by a swan around 1930.
Efforts to control the swan population have met with little success. In Rhode Island, wildlife agency officials shake or “addle” the eggs to prevent them from hatching. (If the eggs are removed from the nest, the female will simply lay-more.) The swan population in Rhode Island has grown almost as fast as it has in Massachusetts, where egg addling has not been tried.
The most common way to control waterfowl populations is to establish a hunting season. Although mute swans have no protection in some states and can be killed humanely by landowners, no state has established a season on the birds. “I have not heard of any push by sportsman groups or wildlife biologists for a hunting season,” said Bill Davis, Massachusetts Fisheries and Wildlife spokesman. “I think there would be great opposition to it.”
Heusmann said a swan-hunting season would not involve hunters picking off birds on a neighborhood pond, where the discharge of a firearm would be illegal anyway. Like other waterfowl hunting, it would have to be conducted along the coast when the birds are in flight, he said. Heusmann stressed there is no serious talk about a swan season, and all that officials can do now is monitor the bird’s expansion. “The problem is that they are white. They’re in the Boston Public Garden. They’re pretty. It’s like the “Ugly Duckling” story. In the case of the swans, though, the ugliness is on the inside,” he said.