The Mute Swan (Cygnus olor) is a common Eurasian member of the duck, goose and swan family Anatidae.
This bird is found mainly in temperate areas of Europe and western Asia. It is not normally migratory, but some populations are forced to move in winter when waterways and lakes freeze. They are sometimes found at the coast, particularly in winter, rather than solely being birds of inland waters.
For aesthetic reasons, this species is often kept in captivity in areas where it is not native in order to decorate parks and ponds. The descendants of such birds have become naturalized in the eastern United States and Great Lakes, much as the Canada goose has done in Europe. In some locations, such as Chesapeake Bay, the numbers of these feral birds have increased to the point where they are considered pests because they compete with native birds for habitat and food.
This large swan ranges from 125-155 cm long with a 200-240 cm wingspan. They may stand over four feet (1.2 m) tall. Males are larger than females and have a larger knob on their bill. The Mute Swan is one of the heaviest flying birds, with males weighing more than 27 lb (12kg), and females more than 25 lb (11 kg).
Its size, orange-reddish bill and white plumage make this swan virtually unmistakable. A similar species is Whooper Swan, but that has a yellow and black bill, and lacks the curved “swan” neck, is longer and heavier and lacks the characteristic projection above the bill.
Juveniles, called “cygnets”, are not the bright white of mature adults, and lack the bright orange bill. The color of the down may be a dull white or gray, and controversy exists over whether the color is related to their gender.
Mute Swans nest on large mounds that they construct in the middle of a shallow lake. These birds mate for life and will reuse the same nest each year, restoring or rebuilding it as needed. Male and female swans share the care of the nest, and once the cygnets are fledged it is not uncommon to see whole families looking for food. They feed on submerged aquatic vegetation, reached with their long bills.
Although this bird can be tame, especially to those who feed it daily, it is aggressive in defense of its nest. Its size and impressive hissing make it a formidable adversary for animals as large as a fox. A grunt, on the other hand, may be a positive signal. There have been many reports of Mute Swans attacking people who enter their territory.
The Mute Swan is, however, less vocal than the noisy Whooper and Bewick’s Swans; the most familiar sound associated with Mute Swan is the whooshing of the wings in flight once this bird has laboriously taken off from the water. Unlike Black Swans, Mute Swans are strongly territorial. The familiar pose with neck curved back and wings half raised is a threat display.
The Mute Swan is protected in most of its range, but this has not prevented illegal hunting and poaching.