The whooper swan (pronounced hooper), Cygnus cygnus, is a large Northern Hemisphere swan. It is the Eurasian counterpart of the North American trumpeter swan. An old name for the whooper swan is 'Elk'; it is so called in Francis Willughby and John Ray's Ornithology of 1676.
The whooper swan is similar in appearance to the Bewick's swan. It is larger, however, at a length of 140–165 cm (55–65 in) and a wingspan of 205–275 cm (81–108 in). Weight typically is in the range of 7.4–14 kg (16–31 lb), with an average of 9.8–11.4 kg (22–25 lb) for males and 8.2–9.2 kg (18–20 lb) for females. The verified record mass was 15.5 kg (34 lb) for a wintering male from Denmark. It is considered to be amongst the heaviest flying birds. Among standard measurements, the wing chord is 56.2–63.5 cm (22.1–25.0 in), the tarsus is 10.4–13 cm (4.1–5.1 in) and the bill is 9.2–11.6 cm (3.6–4.6 in). It has a more angular head shape and a more variable bill pattern that always shows more yellow than black (Bewick's swans have more black than yellow).
The whooper swan is similar in appearance to the Bewick's swan. It is larger, however, at a length of 140–165 cm (55–65 in) and a wingspan of 205–275 cm (81–108 in). Weight typically is in the range of 7.4–14 kg (16–31 lb), with an average of 9.8–11.4 kg (22–25 lb) for males and 8.2–9.2 kg (18–20 lb) for females. The verified record mass was 15.5 kg (34 lb) for a wintering male from Denmark. It is considered to be amongst the heaviest flying birds. Among standard measurements, the wing chord is 56.2–63.5 cm (22.1–25.0 in), the tarsus is 10.4–13 cm (4.1–5.1 in) and the bill is 9.2–11.6 cm (3.6–4.6 in). It has a more angular head shape and a more variable bill pattern that always shows more yellow than black (Bewick's swans have more black than yellow).