Introduction

The Trumpeter Swan is the largest species of native North American waterfowl. It is a long-lived, social species, conspicuous by its large size, all-white plumage, and trumpetlike call. Although it was formerly abundant and geographically widespread, its numbers and distribution were greatly reduced during the early fur trade and European settlement (1600s-1800s), when it was prized for its skins and feathers. Only 69 individuals were known to exist in 1935, but unrecorded flocks also inhabited parts of Alaska and Canada. Numbers have steadily increased with modern conservation, including protection from shooting, habitat preservation, and restoration programs. A 1990 continentwide survey found 15,630 individuals in the wild.

Because of its delayed maturation, single broods, highly variable production, and high winter mortality, population growth of this species is usually slow. Although its numbers and distribution are increasing, populations are still at risk from continued loss of wintering habitat, concentration of wintering flocks at relatively few sites, lead poisoning, and lack of migration in several wild and restored flocks.

Trumpeter Swans use a variety of breeding and wintering habitats that provide open water, access to food, and security from disturbance. Migratory behavior differs widely among various flocks. This, along with specific patterns of habitat use and demography, make it mandatory to manage flocks on an individual basis.