But only the tundra swan, formerly known as the whistling swan, is native to North American. Tundra swans are large white birds, weighing an average of 14 to 16 pounds, with b lack legs and feet. A small yellow spot in front of the eye marks the base of its mostly black bill. A long neck, as long as its body, is held straight or slightly curved.
Tundra swans are monogamous, forming pairs in autumn.
In spring, they leave their wintering areas and return to the arctic and subarctic regions of North America and northeastern Siberia. From May to June, they nest on islets, peninsulas and elev ated hummocks of the open tundra. A pen will lay 3 to 4 eggs that she will incubate for 35 to 40 days, although the cob may sit on the nest while she feeds, mostly at night. The young are ready to fly after two months. Tundra swans winter across the United States.