Wild swans need all the help they can get. The trumpeter swan has a trumpet-like call whereas the tundra swan has a whistling call, and the mute swan is relatively silent. In a standing position, trumpeter swans are approximately 4 feet high. However, if the neck and legs are outstretched they can measure nearly 6 feet long from bill to feet. Wingspans in adults can vary from 6to 8 feet.
Males are typically larger than females.
Sexes can not be told apart, since both have identical white plumage with black bills and feet. Although cob and pen sizes can be told apart if they are side by side, there is still a fair degree of individual variation. Therefore, the only reliable way to sex individual swans is through a cloacal examination. Trumpet swan cygnets are typically born gray in color and steadily lose their gray plumage becoming pure white by the time they are one year old. The bill of adult leucistic trumpeter swans remains black.