The Tundra swan is a small swan that lives in Holarctic regions. Its feathers are white, though sometimes its head and neck feathers become slightly red if it is in an area of iron-rich food. It has black legs, feet and beak and close to its eyes there is a distinctive yellow mark. Babies are gray with pink beak, feet and legs. They develop adult plumage within two years.
Tundra swans are natives of regions of North America, Asia, Europe, north Africa, and the Caribbean. Tundra swans of North America are migratory and consist of two populations: an eastern population and a western one. During the summer mating season, the western birds inhabit Alaska's southwestern coast, from the Aleutian Islands to Point Hope, and above Canada's Arctic circle. During the winter, they live in the Arctic slope in Alaska to the Californian Central Valley. In the summer mating season, the eastern birds live in the Pacific Ocean and migrate southward via Canada, and into North America's Great Lakes region. During the wintering season, the swans inhabit Maryland, Virginia, Georgia, North Carolina, South Carolina, and Florida. Tundra swans live in freshwater pools, lakes, grasslands, and marshes. At the time of migration, they occur in lakes and rivers along their migratory route.
Tundra swans are social birds and interact with others within their population. The most stable unit for a swan is the family, which consists of both parents, the 3 to 7 cygnets they have produced that year, and sometimes young from previous years. These swans forage by dipping their heads and upending while in shallow water. They graze on land, digging with their bills. They will sometimes feed when it is a moonlit night. Aggressive encounters are related to dominance in a hierarchy. Males establish dominance by fighting to protect their families. Swans in the same family use pre-flight signals to ensure that family members take off at the same time. Males tend to lead flights in the autumn and the females in the spring. Such signals include opening the wings, head bobbing, neck stretching and bending repeatedly prior to flight, and other visual displays.
Tundra swans are herbivorous and consume plants, including grasses, sedges, and smartweed. Grasses they eat include mannagrass and seagrass. The swans prefer the flowers, stems, tubers and roots. They eat some invertebrates like shellfish.
Tundra swans are monogamous, staying with the same mate over their lifetime. They choose mates of similar age and size, and so the largest and oldest pairs are generally more dominant. To help in establishing dominance, males fight in order to protect their mates. Mating pairs breed every year, in late May until late June, both parents helping in raising their young. They build nests of vegetation, often sedges, moss and grasses, placing the material on dry elevated ground. Females lay 3-5 yellowish to white eggs and incubation lasts for 31-32 days. The cygnets are cared for by both male and female and remain in the nest for three days. The young fledge around 60-75 days after they hatch. Until about the age of 2, the cygnets follow their mother closely. Sometimes siblings will rejoin their family, either with a mate or without one. Tundra swans can reproduce at 3 years old, but may not begin mating until the age of 4 or 5.
Tundra swans are threatened by the loss and degradation of wetland habitats as a result of drainage (e.g. peat-extraction, petroleum pollution, and changing wetland management practices) and the mowing and burning of reeds. The Arctic breeding habitat is threatened by gas and oil exploration. The species is further threatened by oil pollution (oil spills) in pre-migrational staging and molting areas, from collisions with powerlines, from lead poisoning from fishing weights and lead shot ingestion on wintering grounds and during migration. The Tundra swan is a victim of poaching in north-west Europe and hunting for sport in North America as well as hunting for subsistence in all of its range.
The global population of the Tundra swan, according to the Birdlife resource, is estimated to be 317,000-336,000 individuals, including 5,000-6,000 pairs in Europe, 50-10,000 wintering birds in China and 100-10,000 breeding pairs in Russia. Currently Tundra swans are classified as Least Concern (LC) on the IUCN Red List.