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In page Tundra swan:

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Whistling swans weigh 9.5–21 lb (4.3–9.5 kg) – 16 lb (7.3 kg) on average in males and 14 lb (6.4 kg) in females –, and measure 47–59 in (120–150 cm) in length. Each wing is 19.7–22.4 in (50–57 cm) long; the tarsus measures 3.7–4.5 in (9.4–11.4 cm) in length, and the bill is 3.6–4.2 in (9.1–10.7 cm) long. C. c. columbianus is distinguished from C. c. bewickii by its larger size and the mostly black bill, with just a small and usually hard to see yellow spot of variable size at the base. It is distinguished from the largely allopatric trumpeter swan (C. buccinator) of North America by that species' much larger size and particularly long bill, which is black all over except for the pink mouthline, which is stronger than in the whistling swan.[3][4]