Cygnus buccinator

C. cygnus and C. buccinator have been considered conspecific by some authors (AOU 1983). See Meng et al. (1990) for information on variability of DNA fingerprints in C. cygnus, C. olor, and C. columbianus.

Although Pacific Coast population is increasing, the Rocky Mountain population has moderately increased, and the Interior population of midwestern, northern, and Canada subpopulations have expanded, serious threats to winter habitat availability and quality are present for all three major populations. The Pacific Coast population continues to lose wintering habitat in Washington and British Columbia. Some areas of Alaska breeding habitat are open to development; no overall swan management plan has been enacted for the state. Serious potential for disease outbreaks on reduced winter ranges exist. Species is sensitive to disturbance and pollution.

BREEDING: Formerly throughout North America from central Alaska to western Hudson Bay (James Bay), southeast to Nova Scotia, with the southern limit extending to northwest Mississippi and eastern Arkansas in the east and possibly California in the west. Present breeding range includes Alaska (Interior, Southcentral, Gulf of Alaska, and Chilkat basin), Yukon, British Columbia, Alberta, Washington, Oregon, Nevada, Montana, Idaho, Wyoming, South Dakota, Minnesota, Wisconsin, Michigan, Saskatchewan, and Ontario (Mitchell 1994). Alaska contains over 85% of the world's breeding population, and breeding areas outside of Alaska are very localized (Mitchell 1994).

NONBREEDING: Formerly from the present range in southeast Alaska (a few small flocks along the Gulf of Alaska), along the British Columbia coast, Washington, Oregon, and occasionally California but historically extending to southern California, possibly Arizona and New Mexico, along Gulf Coast to central Florida, and along Alantic coast as far as ice free waters existed (Mitchell 1994). Present range includes the Gulf of Alaska coast, southeast Alaska, British Columbia, western Washington, western Oregon, occasionally California, eeastern Nevada, western Utah, southern Montana, eastern Idaho, northwestern Wyoming, southwestern South Dakota, and small resident populations in the midwestern states, Saskatchewan, and Ontario (Mitchell 1994). In the contiguous United States and adjacent Canada, the highest winter densities occur in western Wyoming, western British Columbia (coast and interior lakes), southeastern Oregon, and southwestern Montana, mainly on wildlife refuges (Root 1988).

Interior population (resulting from transplants and captive propagation) consists of flocks in Lacreek National Wildlife Refuge, South Dakota, and Hennepin County Park Reserve District, Minnesota; these gradually are exhibiting southward movement in fall but still are dependent on supplemental feeding.

Rocky Mountain population nests in the Rocky Mountains of Canada and the United States (Idaho, Montana, Wyoming) and winters primarily in the Greater Yellowstone Ecosystem (Spahr et al. 1991). Breeding areas in Canada include Peace River area of Alberta and British Columbia and Toobally Lakes area of Yukon, plus some areas farther north in Northwest Territories (Johnson and Herter 1989). U.S. flocks of the Rocky Mountain population currently summer in three locations (1) the Tri-state Area of eastern Idaho, southwestern Montana, and western Wyoming, (2) the Ruby Lake National Wildlife Refuge, and (3) Malheur NWR and Summer Lake area of Oregon. Trumpeter swans at Ruby Lake and Malheur NWRs were derived primarily from swans that were transplanted from Red Rock Lakes NWR, beginning in 1941 (Pacific Flyway Study Committee 2002).

There are three regional populations (Pacific Coast, Rocky Mountain, and Interior) recognized by the USFWS (Mitchell 1994). An unknown number of breeding areas exist within the range of these populations (estimated at between 20 and 50 in all regions). Occurences have been searched for extensively, continent-wide survey was conducted in 1990 (Mitchell 1994).

Pacific Coast population (Mitchell 1994) faces a serious threat of winter habitat loss to development. Rocky Mountain population faces a serious threat due to declining winter habitat, overcrowding on existing winter habitat, and potential for widespread disease introduction. Threats to Interior population may be the same winter habitat and disease threats that the Rocky Mountain population faces.

Trumpeters swans are sensitive to human disturbance (boating, float-plane use, photography, etc.) (Mitchell 1994)and pollution. They are unusually sensitive to lead poisoning due to habitat and foraging behavior. White Phosphorus from military operations has caused death at Eagle River Flats, Alaska (Mitchell 1994). Human activity near nest site may cause nest failure or cygnet loss by disturbing adults (responses by pairs varies) (Mitchell 1994). Vulnerable to illegal hunting or malicious shooting due to their conspicuousness and large size (Mitchell 1994).

Rocky Mountain population:
From 1935-1992, the trumpeters were fed grain during winter at Red Rock Lakes National Wildlife Refuge, 20 miles northwest of Harriman State Park, Idaho. Large sanctuaries in Yellowstone and Grand Teton National Parks and at Harriman State Park also protected the swans from human disturbance. Artificial feeding and sanctuaries saved the population from extinction but discouraged southward migration, which is essential to long-term recovery. Artificial feeding at Red Rock Lakes ceased in 1992.
In eastern Idaho, lack of dispersal southward has created a severe "bottleneck" as increasing numbers of trumpeters arrive from Canadian nesting areas to spend the winter within Harriman State Park on the Henry's Fork of the Snake River in eastern Idaho. At this site, which receives the greatest amount of swan use, the aquatic plants can no longer provide enough winter food to support the increasing flocks of swans, Canada geese, and ducks (U.S. Fish and Wildlife Service).
In the Yellowstone region, nest flooding is the primary cause of nest failure, and coyote predation is the major cause of swan mortality in the winter.