Courtesy Kenn Kaufman
Tundra Swans breed in low densities close to coastal areas from the Aleutian Islands north and east to Baffin Island, Canada. This swan also breeds around Canada's Hudson Bay. Tundra Swans sort themselves into eastern and western wintering populations. Western swans winter along the Pacific coast and at scattered interior locations that do not freeze, while eastern swans winter from New Jersey to South Carolina.
A legend for the range map to the right can be found here
Throughout the Arctic coastal plain, Tundra Swans breed on marshes and wet grasslands on or near freshwater pools, slow streams, and lakes. Pond weed, Hoppner's and water sedges, and tall cotton and pendent grasses characterize these sites. Avoiding ice, post-breeding swans move to Arctic salt marshes, then south into the wetlands of the boreal forest, the shallows of lakes and rivers, and finally, coastal salt marshes. Increasingly, Tundra Swans choose wetlands near farm fields, where they can forage on grain.
Like other swans, Tundra Swans have a mostly vegetarian diet that changes with the seasons. Using its long neck, this swan reaches for submerged plants, pulls stems and tubers, and gleans seeds from land and water. During the warmer months, these swans consume sago and Arctic pond weed, grasses, algae, sedges, and crustaceans loosened from the mud with its feet. Agriculturally grown cereal grains are an important component of this bird's diet during migration and winter.
At two or three years of age, Tundra Swans form life-long, monogamous pairs, often after short-term alliances with other partners. Pairs arrive on the breeding grounds together and usually reoccupy an old nest on a traditional site. Courtship displays include mutual greetings with quivering wings and strident calls. On or near water, the pair builds the nest together, but the female forms the bowl. The nest consists of a mound of vegetation, which enlarges with subsequent use, the growth of transplanted sod, and frost heaves.
The female lays four to five whitish eggs and does most of the incubation, which lasts about 31 days. The gray to yellowish hatchlings can soon walk, hide, and feed. From the time the eggs are laid until the family breaks up during spring migration, parents vigorously defend their offspring from predators like foxes, and competitors like other swans and geese. Parents may hiss, extend their wings, and even charge predators. After leading hatchlings to feeding sites, parents may stir food to the surface for the young. Family groups migrate and winter together, and extended family groups may form alliances outside the breeding season.
Flying as high as 8,000 feet, family groups of Tundra Swans migrate in small to large V-shaped flocks. Each population follows traditional routes, modified by weather and the need for food. Flocks depart wintering grounds in February or March to begin arriving in early May. In September, Tundra Swans fly south from Arctic coastal staging areas and arrive between November and December. Many Tundra Swans are either staging or migrating for more than half the year.