Tundra Swans breed on lakes, ponds and pools situated along river deltas in Alaska and Canada, with some birds nesting at inland sites below treeline. Breeding birds prefer areas with extensive wetlands and lakes with long shorelines that support pondweed. In fall, flocks gather (or “stage”) along the brackish shorelines of river deltas before moving south, stopping along the way at wetlands in boreal forests. Wintering flocks gather on estuaries, lakes, bays, ponds and rivers, often situated close to agricultural fields where the birds feed. Back to top
Tundra Swans eat mainly plant matter, although they also eat mollusks and arthropods. Plant foods include tubers, stems, and leaves of aquatic vegetation such as Carex sedges, saltmarsh starwort, alkali grass, pondweed, and Nostoc algae. During migration and on the wintering grounds (especially in the East) look for Tundra Swans in fields gleaning corn, soybeans, and rice left after the harvest, and feeding on growing winter crops such as winter wheat, rye and barley. In the Chesapeake Bay Tundra Swans use their bills and feet to root up clams from the muddy bottom. When feeding on the water Tundra Swans “tip up” like dabbling ducks to reach submerged vegetation. On their arctic breeding grounds they also graze on upland or wet-meadow tundra. Back to top
Nests are typically placed near a large body of water, either on an island or in upland or wet meadow tundra. Tundra Swans often place the nest on the low, elevated ridges between small ponds (known as polygon ponds) that are created by repeated thawing and freezing of arctic soil.
Both members of the pair build the nest, a mound of vegetation including grasses, sedges, other tundra plants, lichens, and moss. The birds pull material from within about 10 feet of the nest site in a ritualized set of behaviors called “forward building” and “side building.” The female uses her feet and body to scrape a cup-shaped bowl into the mound, although both pair members deepen the bowl with their bill. Built in 4 - 9 days before egg laying starts, the nest reaches 8 inches in height, 10 - 20 inches across at the base, with a cup measuring 7.5 - 15 inches wide and 4 - 8 inches deep. The pair continues to work on the nest during egg laying and incubation, and pairs often reuse the nest in subsequent seasons.
|Clutch Size:||3-5 eggs|
|Egg Length:||3.5-4.6 in (9-11.6 cm)|
|Egg Width:||2.3-2.9 in (5.9-7.4 cm)|
|Incubation Period:||31-32 days|
|Egg Description:||Creamy white, often stained tan by nest material.|
|Condition at Hatching:||Eyes open, chick covered in light gray down with light pink legs and toes; able to walk several hours after down dries. Is able to fly at 65 days after hatching.|
Tundra Swans can take off easily from land or water and fly with their necks extended straight out and their black legs trailing behind. Tundra Swans form life-long pairs that remain together year round. Pairs defend a breeding territory of open water and tundra up to a half-acre in size and chase off other swans, geese and Long-tailed Ducks. Such encounters can get physical, with the swans tackling and trampling an intruder or grabbing the tail during an aerial defense. When they’re not breeding Tundra Swans form large, gregarious flocks that travel, forage and roost together. Wintering birds foraging for clams in Chesapeake Bay often go head to head with Ring-billed, Herring, and Greater Black-Backed Gulls that swoop in to steal their prey. Back to top
Tundra Swans are North America’s most numerous swan species. Their numbers fluctuate annually, particularly in the western breeding population, but overall populations were stable between 2006 and 2015. Surveys in 2015 by the U.S. Fish and Wildlife Service estimate about 117,100 Tundra Swans in the eastern population and about 56,300 in the western population. Tundra Swan is not on the 2014 State of the Birds Watch List. There is an annual, regulated hunting season for Tundra Swans. Threats to these birds include lead poisoning by spent shot, fishing sinkers, and mine wastes deposited in sediments. Birds are also killed by diseases, including avian cholera, and a nematode (Sarconema eurycerca) may have caused Tundra Swan deaths in the Chesapeake Bay. Oil and gas drilling in arctic breeding habitats and loss of wetlands at migratory stopover sites, particularly in the Midwest’s prairie pothole region, are all potential threats to Tundra Swans.Back to top
Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.
Limpert, R. J. and S. L. Earnst. 1994. Tundra Swan (Cygnus columbianus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
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U.S. Fish and Wildlife Service. 2015. Waterfowl population status, 2015. Washington, DC: U.S. Department of the Interior.