LITTLE ROCK – Mute swans are a non-native, invasive species that cause problems for native fish and wildlife, and degrade important wetland habitat. Because of the species’ potential negative impacts, the Arkansas Game and Fish Commission recently captured a mute swan and four hybrid cygnets on Harris Brake Lake in Perry County.
The adult mute swan is a pinioned bird, a sign that it was likely a captive bird illegally released into the wild. AGFC Code 09.03 prohibits the release of wildlife without prior written approval of the Commission. The cygnets were the products of a pairing between the mute swan and a native trumpeter swan, and were removed from the wild because of threats to the genetic integrity of trumpeter swan populations.
The trumpeter swan, a native waterfowl species that was restored to the Mississippi Flyway in the 1960s, is on the state’s list of Species of Greatest Conservation Need. The AGFC’s recent removal of the mute swan and the hybrid cygnets eliminates a threat to trumpeter swan breeding success and is part of the AGFC’s commitment to the North American Trumpeter Swan Restoration Plan.
In addition to the threat they pose to native trumpeter swans, mute swans compete for resources with native waterfowl species, and in some cases may displace native water birds. Mute swans are one of the world’s most aggressive waterfowl species and displace native water birds from their nesting and feeding areas by attacking, injuring and even killing them.
Mute swans, a species native to Europe that was introduced to the U.S. in the 19th century, eat as much as 8 pounds of aquatic vegetation a day. They also pull up additional vegetation by the roots while feeding in an area, reducing the availability of these plants to native wildlife. These wetland plants also play a crucial role in aquatic ecosystems by providing food and cover to a variety of vertebrate and invertebrate species. Many wildlife and fish species feed on animals that live in these plants and use the vegetation for nesting and shelter. The removal of the plants by mute swans can negatively affect an entire wetland ecosystem.
Mute swans also exhibit aggressive behavior toward humans. They are large birds and have little fear of humans. Each year, the AGFC and other wildlife agencies across the U.S. receive reports of mute swan attacks on people in watercraft and on shorelines. In 2012, an Illinois man in a kayak died after being attacked by a mute swan.
Mute swan populations can expand rapidly. Michigan, which is home to more than 15,000 mute swans, saw its population grow by more than 10 percent annually prior to that state’s implementation of control measures. Several states in the Atlantic Flyway, including New York, Rhode Island and Maryland, also have experienced rapid expansion.
Mute swans are not protected by federal law, and numerous conservation organizations support the removal of the birds from the wild. The National Audubon Society, the American Bird Conservancy, Ducks Unlimited, the Wildlife Management Institute, the International Association of Fish and Wildlife Agencies and The Waterbird Society are just a few of the organizations that have endorsed the removal of mute swans from the wild.
The AGFC will give the owner of the adult mute swan five days to produce documentation showing legal ownership of the bird and to provide an enclosure from which the swan cannot escape. If no one comes forward, the bird will be euthanized according to guidelines and recommendations from the U.S. Department of the Interior, the Southeast Cooperative Wildlife Disease Study and the American Veterinary Medical Association. The cygnets will be euthanized following the same recommendations. The adult mute swan and cygnets were not given to a zoo, park or other organization because there were no license organizations that could guarantee the swans would be unable to reproduce and add to the growing mute swan problem.