The Tundra Swan, once known as the Whistling Swan in North America, is the most numerous and widespread of the two swan species native to this continent. A separate subspecies of Tundra Swan-Bewick's Swan (C. c. bewickii)-inhabits Europe and Asia. While the latter is fairly well-studied, the literature on Tundra Swans in North America is surprisingly limited. Only in the last twenty years have studies begun to provide basic information on such key aspects of this subspecies's life history as distribution on its migratory routes and breeding grounds, parental care and reproductive success, population dynamics, and demography. While taxonomy demands that this account be entitled Tundra Swan, it actually concerns (unless otherwise specified) only North America's Tundra Swan, a subspecies that many people continue to call the Whistling Swan (C. c. columbianus).
Breeding on arctic wetlands and wintering on estuaries along the East and West coasts, the traditional inland, cross-continent migratory routes of North America's Tundra Swan make it the most likely to be encountered in the field. A long-lived species, this swan forms monogamous pairs. Each year's young remain with their parents until their arrival back on the breeding grounds the following year. Historically, the Tundra Swan's diet consisted primarily of submerged aquatic vegetation and benthic organisms, but drastic declines in such vegetation at some migratory stopover sites, and especially at wintering areas, have driven this species to feed extensively in grain fields. This has lead to conflicts with farmers alleging crop damage. Since being afforded complete protection from hunting by the 1918 Migratory Bird Treaty, populations of North America's Tundra Swan have increased to the point where a limited hunt by permit was begun on the western wintering population in 1962 and on the eastern wintering population in 1984.