Breeding across the Arctic tundra of Alaska and Canada, North American tundra swans are represented by two populations, each currently comprised of about 100,000 birds. The western population, which breeds in Alaska, winters on estuaries of the Pacific Northwest and on lakes of California's Central Valley and the Great Basin.
The eastern population, which often stops to rest and feed in wetlands along the Great Lakes during migrations, winter primarily on coastal bays of the Mid-Atlantic region. Nevertheless, small flocks may turn up anywhere between these major wintering areas, including lakes along the Front Range of Colorado and New Mexico, reservoirs of the Great Plains and riverine wetlands along the Missouri, Mississippi, Arkansas and Ohio Valleys.
Resting on open waters, these magnificent birds feed primarily on aquatic vegetation and on waste grain in nearby agricultural fields; they are also known to consume clams and other marine invertebrates. Like snow geese, their spring migration (which peaks from February to March) is often more gradual and less direct than their autumn flights and the swans generally travel in smaller flocks. Smaller and slimmer than trumpeter swans, tundra swans are also identified by their high-pitched calls (hence their nickname: "whistling swans") and by a small yellow patch at the base of their bill.
