TRUMPETER SWAN (Cygnus buccinator)
With an average body mass of nearly 12 kg for males, the Trumpeter Swan is the heaviest native bird in North America and is one of the heaviest flying birds in the world. Named for its distinctive trumpeting call, this majestic species was extirpated from much of its historic range when thousands were killed, and their skins and feathers shipped to England, in the 19th century (Banko 1960, Houston et al. 1997). Owing to conservation efforts that began in the 20th century, numbers are increasing and distribution is expanding. The present natural breeding range extends from c. Alaska, Yukon, and Northwest Territories to sw. Montana, nw. Wyoming, and ne. Idaho. Trumpeters that breed in Alaska and w. Yukon winter from s. Alaska to nw. Oregon, whereas birds that nest in c. and e. Yukon, Northwest Territories, British Columbia, and Alberta winter in the Tristate Area of Montana, Idaho, and Wyoming. Swans that nest south of Canada remain close to their breeding grounds year-round. “Restoration flocks” have been established, with varying success, in Oregon, Nevada, Montana, South Dakota, Minnesota, Wisconsin, Nebraska, Iowa, Michigan, and Ontario.
Status and Occurrence: Locally common breeder in Beaverhead, Madison, Gallatin, and Lewis and Clark Cos., with most of the birds occurring in the Centennial Valley in and around Red Rock Lakes NWR. Small numbers of reintroduced birds inhabit the Paradise Valley, the Flathead Indian Reservation, and the Blackfoot Valley.
Montana’s Trumpeter Swans are part of the Tristate Subpopulation that occurs year-round near the intersection of Montana, Wyoming, and Idaho. They were the only group in the lower 48 states to survive the declines of the 19th century (Ball et al. 2000). Tristate birds are joined in winter by swans that migrate from Canada (the Interior Canada Subpopulation). In the Centennial Valley, eggs are laid in early May and hatch in mid-Jun; cygnets begin flying in Sep or Oct and remain with their parents in the first winter. Some swans stay in the Centennial Valley year-round, and others migrate short distances to winter in the Madison Valley, se. Idaho, or w. Wyoming.
Counts of adults late in the breeding season increased steadily from 89 in 2004 to 157 in 2007, with 80-90% of the birds occurring in the Centennial Valley (USFWS, unpubl. data). During these same years, from 500 to 1,000 birds wintered in state, most of them (70-77%) in the Hebgen Lake area; other important wintering sites are Ennis Lake and the Centennial Valley (USFWS, unpubl. data). Early specimens were collected on the Yellowstone R. during the Warren Expedition, 27 Aug 1856 (USNM 5470), and at Upper Stillwater Lake, 11 Mar 1902 (FMNH 128938).
Habitat: Nests on freshwater marshes, ponds, and lakes, often on small islands or Muskrat (Ondatra zibethicus) houses that provide protection from mammalian predators. Wetlands used for nesting must be large enough for birds to take flight, contain clean and relatively shallow water, and have a large quantity of aquatic vegetation and invertebrates for food; favored sites often have irregular shorelines (Mitchell 1994). Winters on rivers and other water bodies that provide large stretches (>100 m) of ice-free water that are less than 1.3 m deep and contain an abundance of aquatic food plants (Lockman et al. 1987).
Conservation: Level I Priority and Species of Concern in Montana. Hunting is illegal statewide, but malicious shooting occurs, and some birds are taken inadvertently during the legal hunt of Tundra Swans along the East Front of the Rocky Mts. Collisions with power lines have caused mortality in the Blackfoot and Mission valleys and could occur anywhere swans and humans coexist. Human disturbance can cause nest loss during the breeding season and energetic stress in winter (Mitchell 1994). In recent winters, hundreds of swans have been disturbed by helicopters during Bison hazing at Hebgen Lake. Trumpeters also are sensitive to lead poisoning after ingesting spent shot and fishing sinkers (Blus et al. 1989). The 2005 global population estimate was 34,803 birds, 453 of which summered in the Tristate Area (Moser 2006).
Red Rock Lakes NWR was established in 1935 to protect Trumpeter Swans. Early management practices included impounding warm water and providing supplemental food to keep swans on the refuge throughout the winter, reduce mortality, and improve physical condition of the birds. As a result, swan numbers rose from 30 adults in the 1930s to about 400 in the mid-1950s; numbers varied from 250-400 over the next 20 years and then declined by nearly 50% between 1978 and 1986 (Ball et al. 2000).
Historical Notes: On the basis of a letter written by E. S. Cameron on 30 Apr 1914, Coale (1915: 87) reported that “Twenty years ago Trumpeter Swans were common in Montana…but are now on the verge of extinction.” Saunders (1921: 41) said that Trumpeters were “Formerly a summer resident in suitable localities throughout the state” and that “attempts to locate breeding areas have been unsuccessful.” Banko (1960), however, felt that Trumpeter Swans had been common breeders only in the Red Rock Lakes area and the Flathead Valley, a notion that is more consistent with historical evidence than are the statements of Cameron, Coale, and Saunders.
Lewis and Clark saw few swans in Montana and did not attempt to name those they encountered. On 21 Jul 1805, near present-day Townsend, Lewis described what almost surely were Trumpeters: “we saw three swans this morning, which like the geese have not yet recovered the feathers of the wing and could not fly…we killed two of them…they had no young ones with them therefore presume they do not breed in this country…these are the first we have seen on the river for a great distance” (Thwaites 1904: 255). The next time Lewis reported swans in Montana was 5 Jul 1806 on the Clearwater R. (which he named Werner’s Creek) a few km above its confluence with the Blackfoot R.: “saw two swan[s] in this beautiful creek” (Thwaites 1905: 191). These, too, likely were Trumpeters given the date, but Lewis said nothing to suggest they were breeding. Indeed, the first evidence of breeding was given by Pierre Jean DeSmet, who camped on Flathead Lake with some Salish Indians on 15 Apr 1842 and noted that “The warriors returned in the evening with a bear, goose, and six swan’s eggs” (Thwaites 1906: 359). Hayden (1862: 175) stated that “A few [Trumpeter Swans] breed in the valley of the Yellowstone.” This statement perhaps was made on the basis of the aforementioned specimen taken in late Aug 1856 below the mouth of the Powder R., or perhaps from observations Hayden made a bit farther up the Yellowstone R. during the previous two years. Regardless, there is no evidence that Trumpeter Swans were widespread breeders in Montana during the 19th century.
Evidence for breeding in the Flathead Valley is from Cameron, who reported that “It is generally stated by the Kootenai Indians that they bred in the Flathead Valley up to the first immigration of whites in 1886; but the latest positive record of Trumpeters nesting is in 1881. These swans nested at Lake Rodgers, 20 miles west of Kalispell, at Swan Lake, and on the east side of Flathead Lake, and on the lakes which drain Clearwater, a branch of the Big Blackfoot River” (Coale 1915: 87). The earliest known report of Trumpeters in the Centennial Valley was a second-hand communication from Cameron to Bent (1925: 298) concerning a Kalispell rancher named Forbes: “I [Forbes] punched cows in the Centennial Valley in Beaverhead County from 1883 to 1888. During that time I saw quantities of swans, and killed many young birds which we thought good to eat. We used to paddle after them among the tules…as they never seemed to learn to fly until ice formed around the shores, and were fearless, big, and awkward.”
Citing a monograph by P. M. Silloway, Saunders (1921) reported that one of the most recent breeding records was from the “Highland Lakes” in Fergus County. The information presented by Silloway (1903b: 15), however, is a fanciful second-hand account that casts doubt on the record’s validity: “A friend told me of seeing an old swan and a young one upon the ‘Highland’ lakes. The two were in flight between the lakes, and the cygnet flew only a few feet directly above the elder, so that it could drop on the parent’s back at frequent intervals. The younger swan would fly fifty or sixty yards alone, then drop lightly upon the parent’s back to rest, being carried for fifty to sixty yards in this manner; then it would rise upon its own pinions, and flap along above the elder bird until it again became weary of its own exertions.” How Silloway and Saunders could allow this tale to go unchallenged will forever remain a mystery.
Contemporary Work: Winston Banko, who was a manager at Red Rock Lakes NWR from 1948-1957, reviewed most of what was known about the biology, population ecology, and management of Trumpeters in Montana in his 1960 monograph “The Trumpeter Swan: Its history, habits, and population in the United States.” His analysis showed that as the number of swans increased after the refuge was established, productivity declined and the population leveled off in about 1954 to a number that presumably reflected the carrying capacity of the habitat. He also recommended that the refuge continue feeding swans in winter.
In the years that followed Banko’s landmark publication, it became apparent that swans at Red Rock Lakes often entered the breeding season with poor nutritional reserves, and suffered low reproductive success, owing to harsh winter conditions that were typical of the region (Gale et al. 1987). It was also recognized that many of these swans had lost the tradition of migrating to wintering areas that would allow them to maintain nutritional reserves that were sufficient for successful breeding (Gale et al. 1987). Gale et al. (1987) proposed a long-term management goal for Red Rock Lakes to help establish a migratory group of swans that would use a network of winter habitats outside the refuge. Their recommendations included phasing out winter feeding and encouraging swans to winter at lower elevations in the Tristate Area. The refuge followed these recommendations and ultimately abolished the winter feeding program in 1992 (Ball et al. 2000).
Recent work in the state has focused on restoring breeding birds outside of the Centennial Valley, and swans now occur in three areas as a result of transplants. They were first released in the Paradise Valley in 1989 during the Mute Swan eradication effort that occurred between 1987 and the mid-1990s (McEneaney 2007). The number of adults counted late in the breeding season ranged from 10-17 between 2004 and 2008, and work is confined to monitoring numbers twice annually (USFWS, unpubl. data). Trumpeters were reintroduced on the Flathead Indian Reservation beginning in 1996; two pairs produced four cygnets in 2004, and by 2007 seven pairs produced 16 cygnets that fledged (Becker 2007, Becker and Lichtenberg 2007). The major cause of mortality on the reservation has been collision with power lines. Following the nesting of a wild pair of swans near Lincoln in 2003, more than 70 Trumpeters were introduced to the Blackfoot Valley between 2005 and 2008; by 2007, some of the birds had been documented returning to Montana from wintering sites in se. Idaho (USFWS, unpubl. data).
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