Threats to Birds - Mute Swan (Cygnus olor)
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Photo: Clipart.com |
Overview
The Mute Swan is native
to temperate areas of Europe and western Asia. Because it
is a beautiful bird, this species is often kept in captivity
to decorate parks and ponds. Mute Swans can be found in
the northeastern Atlantic coast and around Lake Michigan
in shallow fresh or brackish water, saltwater bays and marshes
in winter. In 1962, five captive swans escaped their pen
during a storm event and there are now approximately 4,000
Mute Swans in Maryland. In the Chesapeake Bay, Mute Swans
are considered a pest species because they compete with
native waterfowl for habitat and food which is submerged
aquatic vegetation (SAV). By over-grazing Bay grasses,
Mute Swans also eliminate habitat for crabs, fish, and other
wetland dependent species. They are also aggressive, and
in the early 1990s, a large molting flock of Mute Swans
caused a colony of Least
Tern and Black
Skimmer –state-threatened species– to abandon
their nesting site on Barron Island by trampling nests containing
eggs and chicks.
Description
60" long and can stand 4 feet tall. All-white swan with black legs and feet and an orange bill with black knob at the base, curved neck when floating. Males are larger than females and can weigh 27 lbs. Nest on large mounds that they build in the middle of a shallow lake. Aggressively defends its nest and will attack people who enter its territory. Can breed at 3 years of age, and females lay a clutch of 3 - 8 eggs. Cygnets hatch with a gray downy plumage and they can fly in 3 to 4 months. They generally stay with the parents until the next breeding season. Mute Swans can live for over 25 years, though most live 5 or 6 years.
Birds Affected
Compete with Tundra Swans and other native waterfowl for SAVs; cause shorebirds such as Black Skimmer, Least Tern, Forsters’ Tern, and Common Tern to abandon their nests; known to kill Mallard ducklings and Canada Goose goslings.
Control
Egg addling; live capture and removal of adult swans; euthanasia of adult swans; and shooting by professional hunters. Maryland Department of Natural Resources hopes to reduce the state's population through lethal take of 1000 Mute Swans in 2005.
American Bird Conservancy
was closely involved in efforts to remove protection for
non-native bird species through passage of the Migratory
Bird Treaty Reform Act. Passage of this act in 2004
reversed a previous court ruling that treated some invasive
exotic bird species such as the Mute Swan as protected under
the Migratory Bird Treaty Reform Act of 1917.
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