Maryland natural resources officials plan to shoot 1,500 mute swans—almost half of the state’s population of the nonnative bird—to protect underwater grass beds and native species.
The swans, imported from Asia and Europe in the 1800s, weigh up to 25 pounds and annually eat about 10.5 million pounds of Bay grasses, which are the target of major restoration efforts in the Chesapeake.
The Department of Natural Resources has received a federal permit to shoot up to 1,500 of the estimated 3,600 swans. The hunt is planned for the Eastern Shore counties, where most of the birds live, by the end of the year.
Officials say Maryland’s mute swan population began expanding when five escaped from a Talbot County farm in 1962. It has grown to a point where biologists say reducing it has become a necessity. Many of the swans are due to turn 3 years of age, which means they will be old enough to begin breeding and could multiply rapidly if the state doesn’t act.
Left unchecked, biologists say the birds could number 20,000 by 2010.
“Our best experts tell us if we don’t act now, we will have missed a critical opportunity, and we’ll have a huge number of these animals on our hands,” said Jonathan McKnight, associate director of habitat conservation for the Department of Natural Resources Wildlife Heritage Service.
The swans chew on underwater grasses in the spring and fall, when the grasses are reproducing, and in some cases they have destroyed expensive underwater grass restoration projects. Most native waterfowl migrate elsewhere during the critical growing time for grasses, eating them primarily during the winter.
State biologists say the large birds cause multiple problems, such as driving out nesting native waterfowl. In one case, the swans trampled the nests and eggs of a colony of least terns and black skimmers, both of which are listed as threatened species in the state.
Because of their aggressive nature, the swans have even been known to keep people from using the shore near nesting areas.
Mute swans have been shot before in the Bay—a half dozen were killed by state and federal biologists on Barren Island in 1997. The shooting was halted amid public complaints, and a task force was formed to figure out what to do about the birds.
The task force released a preliminary report in 2001 calling for the establishment of “swan free” zones and other actions to protect critical areas for grass beds and native birds.
The DNR’s Waterfowl Advisory Committee endorsed the task force recommendations, but went further by calling for a rapid reduction in the mute swan population and an end to state protection for the species.
The recommendations from the two groups were incorporated into a new statewide mute swan management plan the state released in April, and Gov. Robert Ehrlich ordered DNR officials to begin implementation.
“The overwhelming evidence shows that mute swans contribute to the deterioration of the Bay by consuming its vital submerged aquatic vegetation,” Ehrlich said. “Failure to act now would be simply irresponsible.”
The overall management goal is to keep the mute swan population at a level that minimizes impacts on native species and habitats, minimizes conflicts with humans and is consistent with the objectives of the Chesapeake 2000 agreement.
Specific objectives of the plan include:
- Develop a public outreach program about the mute swan population and its impacts on the Bay.
- Exclude or remove all mute swans from “swan-free areas” to protect habitats critical to the Bay’s living resources.
- Reduce the mute swan population as quickly and efficiently as possible, consistent with activities to protect and restore the Bay’s living resources.
- Prevent the escape of captive mute swans.
- Reduce conflicts between mute swans and people by permitting a wide variety of effective and efficient control methods.
- Monitor the size and distribution of the mute swan population and evaluate the effectiveness of management actions.
- Conduct additional research that will increase understanding of the role of mute swans in the Bay ecosystem and their impact on other resources.
Still, the shooting plan prompted complaints from some.
“The state really doesn’t know so much about this bird, which makes me question why they’re doing this,” said Patrick Hornberger, who enjoys the swans that live on Island Creek near his Trappe home.
But Gerald Winegrad, a vice president of the American Bird Conservancy and a former state senator who has mute swans nesting outside his home near Annapolis, said that he supports shooting the swans because it will save other birds.
“They’re just big, aggressive birds that aren’t indigenous to this area and don’t belong here,” Winegrad said.
McKnight said the hunt will be conducted only by DNR personnel. Most of the shooting will be in public parks and wildlife management areas. The birds will be shot on private land only with the owner’s permission, he said.
McKnight said the shooting will probably be conducted by two teams working from boats. No specific date has been set.
Property owners who want to keep swans on their land may obtain state and federal permits, he said. “We will work and cooperate with private landowners wherever possible,” he said.
The state has been trying to reduce the mute swan population for years by sending volunteers out to spread vegetable oil on their eggs, a process known as “addling” because it keeps the eggs from hatching.
If the eggs are smashed, scientists say, the birds will lay replacements. But mute swans will sit on addled eggs and not lay more. DNR’s federal permit will also allow it to addle the eggs in 350 nests.
But Winegrad said a study of a 20-year egg-addling program in Rhode Island showed that it didn’t work. The swan’s numbers increased fivefold over the 20 years.
Mute swans are long-lived and prolific. They have a 20-year life span, and a female may produce up to 30 offspring.