Thewhooper swan (/ˈhuːpə(ɹ) swɒn/ "hooper swan";Cygnus cygnus), also known as thecommon swan, is a large northern hemisphereswan. It is the Eurasian counterpart of the North Americantrumpeter swan.
The whooper swan is similar in appearance toBewick's swan. It is larger, however, at a length of 140–165 centimetres (55–65 inches) and a wingspan of 205–275 cm (81–108 in). The weight is typically in the range of 7.4–14.0 kilograms (16+1⁄4–30+3⁄4 pounds), with an average of9.8–11.4 kg (21+1⁄2–25+1⁄4 lb) for males and8.2–9.2 kg (18–20+1⁄4 lb) for females. The verified record mass was15.5 kg (34+1⁄4 lb) for a wintering male fromDenmark. It is considered to be amongst the heaviest flying birds.[5][6] Among standard measurements, the wing chord is56.2–63.5 cm (22+1⁄8–25 in), the tarsus is10.4–13.0 cm (4+3⁄32–5+1⁄8 in) and the bill is 9.2–11.6 cm (3.6–4.6 in).[7] It has a more angular head shape and a more variablebill pattern that always shows more yellow than black (Bewick's swans have more black than yellow). Like their close relatives, whooper swans are vocal birds with a call similar to the trumpeter swan.
Whooper swans require large areas of water to live in, especially when they are still growing because their body weight cannot be supported by their legs for extended periods. The whooper swan spends much of its time swimming, straining the water for food, or eating plants that grow on the bottom.[8]
Whooper swans pair for life, and their cygnets stay with them all winter; they are sometimes joined by offspring from previous years. Their preferred breeding habitat iswetland, but semi-domesticated birds will build a nest anywhere close to water. Both the male and female help build the nest, and the male will stand guard over the nest while the female incubates. The female will usually lay 4–7 eggs (exceptionally 12). The cygnets hatch after about 36 days and have a grey or brown plumage. The cygnets can fly at an age of 120 to 150 days.
When whooper swans prepare to go on a flight as a flock, they use a variety of signaling movements communicate with each other. These movements include head bobs, head shakes, and wing flaps and influence whether the flock will take flight and if so, which individual will take the lead.[10] Whooper swans that signaled with these movements in large groups were found to be able to convince their flock to follow them 61% of the time.[10] In comparison, swans that did not signal were only able to create a following 35% of the time.[10] In most cases, the whooper swan in the flock that makes the most movements (head bobs) is also the swan that initiates the flight of the flock – this initiator swan can be either male or female, but is more likely to be a parent than a cygnet.[10] Additionally, this signaling method may be a way for paired mates to stay together in flight. Observational evidence indicates that a swan whose mate is paying attention to and participates in its partner's signals will be more likely to follow through with the flight. Thus, if a whooper swan begins initiating flight signals, it will be less likely to actually carry through with the flight if its mate is not paying attention and is therefore less likely to join it.[10]
They are very noisy; the calls are strident, similar to those of Bewick's swan but more resonant and lower-pitched on average:kloo-kloo-kloo in groups of three or four.
Whooper swans are much admired in Europe.[8] The whooper swan has been the national bird ofFinland since 1981[11][12] and is featured on the Finnish1 euro coin. The whooper swan is one of the species to which theAgreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies. Musical utterances by whooper swans at the moment of death have been suggested as the origin of theswan song legend.[citation needed] Theglobal spread of H5N1 reached theUK in April 2006 in the form of a dead whooper swan found inScotland.[13]
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