Species Assessment for the Trumpeter Swan (Cygnus buccinator) in Wyoming
Gary P Beauvais
Tags: WLCI Agency Report
Weighing 10 - 15 kg and with a wingspan of 2.4m when fully grown, the trumpeter swan (Cygnus buccinator) is the world's largest waterfowl. Trumpeter swans are similar in appearance to other white swans, but their foreheads slope evenly to an all black bill. The more common and smaller tundra, or whistling, swan (C. columbianus) is smaller with a more curved upper bill, and usually has a yellow spot in front of its eye.
The trumpeter swan is a long-lived, social species, conspicuous by its large size, all-white plumage, and trumpet-like call. Although once abundant and widespread in North America, populations were greatly reduced during the European settlement era when the species was prized for its skin and feathers. Historic annual range likely encompassed most of Canada and the United States (Gale et al. 1987).
In 1989 the USDI Fish and Wildlife Service (USFWS) was petitioned to list a portion of the North American population of trumpeter swans as Threatened. In 1990 the petition was denied based on insufficient information to warrant proceeding with a status review. In 2000 the USFWS was again petitioned to list the trumpeter swan population in Yellowstone National Park as Threatened. In January 2003 the USFWS found that the petition did not adequately establish that this population (the “tri-state flock”) was a distinct population segment warranting listing. In Canada the trumpeter swan was listed as a vulnerable species in 1978 (Mackay 1978). After a status assessment conducted in the mid-1990s, the Canadian federal government moved the species to its ‘not at risk’ category (COSEWIC 2002).