DEEP: Mute Swan Fact Sheet

Mute Swan Fact Sheet

MUTE SWAN
Cygnus olor

{Mute Swan Illustration}
Copyright 1997
Habitat: The mute swan, an introduced species, can be found in freshwater ponds, slow rivers, coastal bays, and inland lakes.
Weight: 25 pounds on average
Length: Wingspan: seven to eight feet
Food: Over 95% of the diet is aquatic vegetation. Occasionally, mute swans will also feed on insects and other invertebrates.

Identification: The mute swan is a large, all-white swan recognized by its orange bill which is black at its base. There is also a prominent black knob at the base of its bill. Another distinctive characteristic is the graceful curved neck held in an S-shape with the bill pointed downward while the bird is swimming. The male mute swan, or cob, is usually larger in size with a more prominent knob on his forehead but is otherwise identical to the female, or pen. Young swans, called cygnets, are usually white, but gray-colored cygnets are not uncommon.

Range: In North America, mute swans (7,000 or more) are concentrated along the Atlantic coast from Massachusetts to Maryland with a smaller population in Michigan. Approximately 150 pairs of mute swans have been recorded nesting along the Connecticut coast and up to 20 miles inland along the major rivers, and in some inland lakes and ponds.

Reproduction: Most mute swans breed at age three and remain with the same mate for life. Courtship display begins in late February and each pair vigorously defends a territory (four to 10 acres in size) from other swans. The nest, constructed in late March or early April, is typically a large (4' x 4'), somewhat circular pile of aquatic plants built on an island or in clumps of cattails or grasses along the edge of the water. Flooding is a common cause of nest failure. If a nest is lost, renesting may occur until late spring. An average of four to six eggs are laid in a three to four-inch depression in the nest center and incubated by the pen for 36 to 38 days. The cob becomes most aggressive when defending the incubating pen or young cygnets and will chase and even attack other wildlife and people nearby. Before leaving the nest, young cygnets may be subject to chilling during rainy periods and can die from exposure. After leaving the nest, the cygnets are sometimes preyed upon until they are about 40 days old. Most cygnets have fledged by early fall but will remain with their parents until late fall. Survival after fledging is high and 50 percent of the young can expect to survive through age seven. Mute swans are long-lived (20 to 30 years) and can breed every year after age three. However, the reproductive rate drops considerably after age 20.

History in Connecticut: The mute swan was introduced into the eastern United States from Europe. The Atlantic Flyway population is thought to be the result of several hundred swans transplanted to the lower Hudson River Valley and Long Island between 1910 to 1912. Feral mute swans were reported in Connecticut by the 1930s but establishment of breeding birds did not begin until the late 1950s. The midwinter waterfowl survey recorded mute swans in 1963 with a count of 143. The most recent midwinter survey counts average 1,500, which is 20 percent of the entire Atlantic Coast population.

Interesting Facts: The North American populations of mute swans do not migrate long distances but move from ice-bound freshwater ponds to nearby open coastal bays in the winter where they gather in flocks of 100 or more.

Management of Nuisances: A positive aspect of mute swans in Connecticut is their aesthetic appeal. However, many conservationists consider the mute swan to be an ecologically damaging exotic species. Mute swans' territorial defense of an area may affect native breeding waterfowl populations. A recent study of interactions between mute swans and native waterfowl on freshwater ponds in southeastern Massachusetts concluded that the mere presence and antagonistic behaviors of swans caused native waterfowl to avoid nesting. Not only do the swans compete for nesting areas with other waterfowl, they graze heavily and uproot aquatic vegetation important as a food source for native waterfowl.

Observing mute swans provides a source of enjoyment for some state residents. However, the aggressive nature of the species and its close association with human activity will undoubtedly continue to result in swan nuisance problems. One thing citizens can do to reduce nuisance swan problems is to avoid feeding them. Swans that become used to handouts sometimes get belligerent if the food is cut off.

{Logo} The Technical Assistance Informational Series is 75 percent funded by Federal Aid to Wildlife Restoration - Pittman-Robertson (P-R) Program. The P-R Program provides funding through an excise tax on the sale of sporting firearms, ammunition, and archery equipment. The remaining 25 percent of the funding is matched by the Connecticut Wildlife Division. (rev. 12/99)