Photo credit: Luciano. https://flic.kr/p/mCAv4n

Mute Swan

(Cygnus olor)

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If you believe you have found this species anywhere in Pennsylvania, please report your findings to iMapInvasives by submitting an observation record.

Species at a Glance

Although many people enjoy its beauty, the mute swan is a large and aggressive bird that originated in Europe and Asia. It adversely impacts ecosystems by uprooting valuable aquatic plants, outcompeting native birds, attacking native wildlife and humans, and carrying disease agents like E. coli.

Identification

The mute swan is a very large bird, measuring 142-157 cm (56-62 in) in length and weighing 11-14 kg (25-30 lbs). Adults have all white plumage, vibrant orange bills, and a black knob present above the bill. Young birds have grayish bills. When swimming, the mute swan often holds its wings slightly upraised over its back, forming a hump. The conspicuous curved neck is held in an “S”-shape, with the bill held downward while swimming.

Similar Species

The most notable difference between the mute swan and native swans, like the trumpeter swan (Cygnus buccinator) and the tundra swan (C. columbianus), is that adult mute swans have an orange bill, while the native swans have black bills. The mute swan also has a black knob on top of the bill that is absent in the native swans. The “S”-shaped curve in the mute swan also distinguishes it from the trumpeter swan, which has a “C”-shaped neck.

Habitat

This species can be found in both marine and freshwater environments, including ponds, slow rivers, coastal bays, and inland lakes. It prefers habitats infested with phragmites and cattail that it can use for nesting material and that provide protection from potential predators.

Spread

It is widely thought that all North American mute swan populations originated from the release or escape of individuals from early captive flocks that were brought to the United States for ornamental purposes. Because it is relatively long-lived, reaching over 25 years in some wild populations, the mute swan has the potential to increase its population size rapidly if left unchecked.

Distribution

Native to Europe and parts of Asia, the mute swan was intentionally brought to the United States in the mid- 1800s to the early 1900s to beautify city parks, zoos, and private estates. However, a small number of birds escaped into the wild in New Jersey and New York, allowing Atlantic Flyway populations to form. This species can now be found from southern Ontario to North Carolina, with “semi-domestic” flocks ranging south to Florida.

 

Note: Distribution data for this species may have changed since the publication of the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016), the source of information for this description.

Environmental Impacts

The mute swan is capable of uprooting about 20 pounds of submerged aquatic vegetation per day that would otherwise provide important food and shelter for native fish and wildlife. The mute swan also behaves aggressively toward other birds and even humans. It chases native water birds to keep them from nesting, and in extreme cases, can attack and kill ducklings, goslings, or other small water birds.

Video
Note

Information for this species profile comes from the Mid-Atlantic Field Guide to Aquatic Invasive Species (2016).

The Pennsylvania iMapInvasives Program is a partnership of the Western Pennsylvania Conservancy, the Pennsylvania Natural Heritage Program, and NatureServe.

Funding for Pennsylvania iMapInvasives is provided by the Great Lakes Restoration Initiative.

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Pennsylvania Natural Heritage Program, iMapInvasives partner
Great Lakes Restoration Initiative logo, iMapInvasives funding source