Named for their resonant brassy call, trumpeter swans are a common sight across Denali's skies during the spring and fall and can be found throughout Denali's wetlands in the summer. Those swans that return annually to breed in Alaska number over 17,500 and belong to the Pacific Coast population. The Pacific Coast population makes up about 75% of the world's total number of trumpeter swans. Driven to near extinction by humans in the 19th century, focused conservation measures have helped trumpeter swans wage a comeback. Removed from the Federal Endangered Species list in 1968, current surveys estimate the worldwide population at 24,000 swans.
The rich wetlands of the northwestern and southwestern portions of Denali support large numbers of breeding, brood-raising, and pre-migratory staging swans. In August 2000, US Fish and Wildlife biologists counted over 1,000 trumpeter swans in Denali during the statewide trumpeter swan survey.
Breeding habitat includes freshwater marshes, ponds, lakes, and slow-flowing rivers. Swans build their nests on old beaver houses and dams, and on emergent vegetation, either floating or anchored to the bottom of the water body. Many nests are built offshore and are usually surrounded by a 20 to 30 foot (6 to 9 meter) moat.
The future of trumpeter swans is promising yet tenuous. While populations appear to be slowly on the rise, many dangers still exist and the National Audubon Society lists trumpeter swans as a conservation priority on their nationwide WatchList.
The most serious threats to trumpeter swans include habitat loss resulting from expanding human populations, increases in human disturbance, and lead poisoning. Habitat loss is especially prevalent on the winter ranges. There is increasing interest to develop visitor facilities and new access points in the southern portions of Denali. Because trumpeter swans are highly sensitive to disturbance, park managers must protect swans and their habitat in this area. Working cooperatively with US Fish and Wildlife Service researchers, Denali scientists are conducting surveys to locate nesting and pre-migratory staging swans and describe their habitats in the southern portion of Denali. Using this data, park managers and others will be able to locate new visitor facilities and access routes away from important swan habitat.