"To form a perfect conception of the beauty and elegance of these Swans, you must observe them when they are not aware of your proximity, and as they glide over the waters of some secluded inland pond. On such occasions, the neck, which at other times is held stiffly upright, moves in graceful curves, now bent forward, now inclined backwards over the body. Now with an extended scooping movement the head becomes immersed for a moment, and with a sudden effort a flood of water is thrown over the back and wings, when it is seen rolling off in sparkling globules, like so many large pearls. The bird then shakes its wings, beats the water, and as if giddy with delight shoots away, gliding over and beneath the surface of the liquid element with surprising agility and grace. Imagine, reader, that a flock of fifty Swans are thus sporting before you, as they have more than once been in my sight, and you will feel, as I have felt, more happy and void of care than I can describe." —John James Audubon (1843) (1)
The largest native North American waterfowl, the Trumpeter Swan is a long-lived, social species, conspicuous by its large size, all-white plumage, and trumpet-like call. Although it was formerly abundant and geographically widespread, its numbers and distribution were greatly reduced during the early fur trade and European settlement of North America (1600s–1800s), when it was prized for its skins and primary feathers. Only 69 individuals were known to exist in the contiguous United States in 1935, but unrecorded flocks also inhabited parts of Alaska and Canada. Numbers have steadily increased with conservation, including protection from shooting, habitat conservation and management, and range expansion programs. The 2015 continental estimate of white swan abundance was 63,016, an increase of 28,213 swans since the 2010 survey, and the highest estimate recorded since surveys began in 1968 (2).
Although the overall population growth is encouraging, because of its long life, delayed maturation, single broods, and highly variable production, growth of individual flocks is sometimes slow. And although its numbers and distribution are increasing, some populations remain at risk from low survival rates, poor quality breeding habitat, continued loss of wintering habitat, concentration of wintering flocks at relatively few sites, and/or lead poisoning. Therefore, the trends and status of individual flocks and metapopulations must be viewed spatially, temporally, and contextually.
Trumpeter Swans use a wide variety of breeding and wintering habitats that provide open water, access to food, and security from disturbance. Migratory behavior also differs widely within and between flocks. This, along with different patterns of habitat use and demography, makes it necessary to manage individual flocks, and in turn, to have biological and behavioral data for individual flocks.
The most comprehensive references on the Trumpeter Swan are Banko (3), Hansen et al. (4), Baldassarre (5), and the unpublished reports by Gale et al. (6), and Lockman et al. (7). Much useful information is contained in The Trumpeter Swan Society's newsletters and in their journal North American Swans, the Proceedings and Papers of the various Trumpeter Swan Society Conferences, and unpublished university theses. Scott (8) and the International Swan Symposia (9, 10, 11, 12) are also excellent sources on swans, including the Trumpeter Swan.