The Mute Swan (Cygnus olor) is a Eurasian member of the duck, goose and swan family Anatidae. Although they tend to be quieter than other kinds of swans, they are not mute, and do vocalize.
Adults of this large swan range from 125 to 170 cm (49-67 in) long with a 200-240 cm (79-95 in) wingspan. They may stand over 1.2 m (4 ft) tall on land. Males are larger than females and have a larger knob on their bill.
The Mute Swan is one of the heaviest flying birds, with males (known as cobs) averaging about 12 kg (27 lbs) and females (known as "pens") more than 8 kg (19 lbs). An unusually big Polish cob weighed almost 23 kg (50 lbs), surpassing the longer-bodied Trumpeter Swan to make it the heaviest waterfowl ever recorded. Its size, orange-reddish bill and white plumage make this swan almost unmistakable at close quarters. Surveys done by airplane, however, often mistake the species, creating questionable counts. The most similar species is the Whooper Swan, but it has a yellow and black bill, lacks the curved "swan" neck, is longer and heavier, and lacks the characteristic projection above the bill.
Young birds, called cygnets, are not the bright white of mature adults, and their bill is black, not orange, for the first year. The color of the down may range from pure white to grey to a buff color. The grey/buff coloration is most common. The white colored cygnets have a leucistic gene, seen most often in the north central states in America and in Poland. All Mute Swans are white at maturity.
In 2004, a nationwide program in the United States was announced that would reduce Mute Swan populations by 85%, with the remaining swans to be pinioned, neutered and placed in parks. In Canada, no such program was developed. Concurrently, a program to "place" Trumpeter Swans to replace the Mute Swans was formalized, even in areas in which Trumpeter Swans were never shown to exist. The public's response was very unfavorable, as shown by letters to state and federal agencies, outnumbering those of hunters in favor of the action more than a hundred to one, but it was ignored.(U.S. Federal Register, 2004).