Trumpeter Swan

Trumpeter Swan

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Description

The trumpeter swan is the largest species of North American waterfowl. Like all swans, both males and females have identical white plumage. Feathers of immature swans are an ash-gray color, and some gray feathers remain evident on the heads and necks of the swans that are one and two years old. Trumpeter swans have an angular wedge-shaped head profile, with the black of the bill appearing to merge with the eye. The bills are all black, with a red border on the lower jaw.

Lifestyle

Trumpeter swans live in small flocks, often with members of their own family. Their daily routine varies from season to season. In winter they rest more and eat less, while in spring they consume large amounts of food and are very active during the day. Flock size also varies seasonally. In spring, flock size can be almost half that found in the fall because the young have left and the breeding season is about to begin.

Trumpeters are migratory birds. In Alaska, trumpeter swans begin flying south in late September or October, depending on the weather. Many trumpeter swans spend the winter on the western coast of Canada, Alaska and Washington.

Trumpeter swans produce a variety of sounds, but they are known for their low bugle call. They are very social creatures except for in times of mating when they become quite territorial.

Since trumpeter swans have ground nests, they are easy targets for predators such as bears, wolves, coyotes, wolverines and common ravens. Post-hatchlings and adults are prey to fast predators such as coyotes, red fox and golden eagles. The main predator of adult trumpeter swans are humans.

Food Habits

In summer, swans eat foliage, seeds, tubers and various marsh plants. Young cygnets grow rapidly and require a high protein diet of aquatic invertebrates during the first few weeks. Gradually they shift to a vegetable diet similar to that of adults. On staging ground areas and wintering grounds in the Lower 48 states, trumpeter swans have learned to feed in agricultural fields, on vegetables, winter wheat and unharvested grain.

Lifecycle

Swans pair and mate for life, usually as two-year-olds, but delay breeding until their third, fourth, or even fifth year. If one of the pair is lost, a new mate will be found before the next breeding season. Because of the lengthy development period for their young, swans begin nesting as early as spring thaw permits. They select a nest site typically in an undisturbed marsh adjacent to a small lake. Construction begins by uprooting nearby plants to form a nest mound that may be used year after year. When finished, a trumpeter nest is six to twelve feet in diameter and about one to two feet above water level. The female lays two to seven eggs (average four) over the next five to twelve days. While a trumpeter female (called a “pen”) attends to nesting duties, her mate (the “cob”) defends a territory around the nest. The young, or cygnets, hatch after 21 to 35 days of incubation.

Trumpeter swans are monogamous and mate for life. They begin mating at four to seven years of age. Mating usually occurs from March to May. Nest-building can take two to five weeks to complete, and both parents are involved in construction. The nests range from 1.2 to 3.6 m in diameter and are usually surrounded by water. The materials used in nests building include various aquatic vegetation, grasses, and sedges. The female usually lays four to six eggs and incubation lasts for 32 to 37 days, done mainly by the female. The young, called cygnets, begin to swim after 24 hours. They fledge after 91 to 119 days and are independent after one year.

Population Status, Threats & Conservation

The trumpeter swan is more numerous today than it was 30 years ago thanks to the waterfowl conservation movement and the remoteness of their northern breeding range. They were hunted for their feathers throughout the 1600s - 1800s, causing a tremendous decline in its numbers.

Swans are very sensitive to disturbance and may have an unsuccessful breeding season if high levels of human activities occur near their chosen nesting site. In most areas, special habitat protection measures are intended to ensure continued use and production by swans. Recently, eggs from Alaskan trumpeter swans have been sent to several Midwestern states where restoration programs are establishing nesting swans where they have not been seen in 100 years. As with all migratory birds, they are protected under the Migratory Bird Treaty Act.

Sources:
The Cornell Lab of Ornithology
University of Michigan Museum of Zoology Animal Diversity Web
Alaska Department of Fish and Game