Whooper swan  (Cygnus cygnus)

The whooper swan is a winter visitor to Britain. Its common name refers to the loud ‘whooping’ calls that it produces (5). This large white swan tends to hold its neck erect whilst swimming (3). In spring and summer, some adults may develop rusty ‘stained’ plumage on the neck and head caused by the iron-rich water on which they live (6). It can be distinguished from the smaller Bewick’s swan in that the wedge-shaped yellow colouration of the bill extends beyond the nostrils, with the rest of the bill being black; in Bewick’s swans the yellow patch is small and rounded (2). Juveniles have greyish brown plumage and a pink and black bill (2).

Whooper swans breed across northern Eurasia (5). Most of the whooper swans that spend the winter in Britain and Ireland originate from the population that breeds in Iceland (4). The population breeding in north-western Europe winters in Denmark and parts of Germany, and there are two western Siberian breeding populations; one winters in the eastern Mediterranean while the other migrates to the area around the Caspian Sea (4). In Britain a few pairs occasionally try to breed in Scotland, but with varying success (3). The British wintering population is mainly northern, with most birds occurring north of a line drawn between the Wirral to the Humber (5). Further south of this, only small flocks occur with the exception of the Ouse Washes and Anglesey (5).

Whooper swans make use of a wider range of habitats than Bewick’s swans (5). They are found on lowland farmland close to the coast, on flooded fields, mudflats, lakes and small ponds and lochs and will graze on farmland in winter (3) (5). They breed in boggy habitats with pools and small lakes where there are plenty of reeds and other sheltering vegetation (2) (3).

Whooper swans can be seen in Britain from November to March (3). During the migration they fly at high altitudes; a pilot flying at 8,000 feet once saw a flock of swans, thought to be whoopers (6). Although this species may occur in very large flocks numbering over 1000 individuals, they more typically occur in small groups (5). They feed on water plants, grass and cereals and may eat waste potatoes and sugar beet (5).

During courtship, pairs face one another, with the wings held in a half-lifted and half-open position. The neck is then extended and bent repeatedly while both birds loudly vocalise (7). The pair produces a clutch of between three and seven eggs, which are incubated for 35 days. The young, known as cygnets, will have fully fledged after a further 87 days (3).

Known threats facing this species include the risk of flying into overhead wires (7). As this swan overwinters in such large numbers in Britain, and because a handful of pairs attempt to breed in this country, it is included in the Amber list of Birds of Conservation Concern (3).

44% of the British population of whooper swans and 19% of the Irish population occur within Special Protection Areas (SPAs) and so this species receives a level of protection at these sites. However, as this bird tends to feed away from these protected areas, suitable management in the countryside surrounding these areas must be considered (4).

For more on British birds see the RSPB website:
http://www.rspb.org.uk

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk