Size: 60-72" (150-180 cm). A large, pure white swan with long neck, flat head and heavy, all black bill. Swim with neck straight and bill horizontal.
Similar Species- Tundra swan is smaller with a small yellow spot between the eye and the bill. Head rounder, call softer, high-pitched hoo-hoo-hoo given in flight.
A loud, booming horn-like call on one pitch
Breeds in Alaska, western Canadian provinces, southeastern Oregon, eastern Idaho, Montana, and northwestern Wyoming. Introduced and established in Nevada and southwestern South Dakota. Winters primarily from southern Alaska to Montana, and south to northern California, sometimes Utah, New Mexico, and eastern Colorado.
Adults feed on aquatic vegetation, but may also graze in fields. Young eat aquatic beetles and crustaceans, and, after 5 wk, aquatic plants. In Idaho, adults feed primarily on water- milfoil and pondweed; existing evidence indicates that preferred winter food is declining.
Builds nest on ground. Forages on, or just under, water surface. Occurs as resident along Yellowstone Park border; migrant, northern populations winter in Harriman State Park and Island Park. Extensive studies have been done in Idaho on wintering and nesting behavior and habitat. High first-year mortality in Tri-state (WY, ID, MT) cygnet population. Low winter flows and cold conditions can negatively impact wintering swans. Several breeding areas in Idaho outside of Fremont Co. are result of transplants.
clutch size varies from 2-9 eggs, but is usually around 5 (in Idaho study, mean clutch size ranged 3.6-4.4). Both sexes, but mainly the female, incubate eggs. Incubation lasts 33-37 days. Nestlings are precocial, but remain with adults until subsequent spring. Fledging period lasts 100-120 days. In Idaho, productivity of Trumpeter Swans has decreased in last 10 yr, perhaps due to poor cygnet survival.
|Status:||Protected nongame species|
Gale, R.S., E.O. Garton, and I.J. Ball. 1987. The history, ecology, and management of the Rocky Mountain population of trumpeter swans. Idaho Dept. Fish & Game, Boise. 314pp.