Bewick's swan

Voice

Higher, more talkative and more chattering than Whooper: a muffled, nasal, undulating koo-koo-kooloo, heard from a feeding flock as continuous babble. The flight call is a softer, cheerful kow-kow. Best heard as flocks leave and return to the roost in November and December, and at dusk.

Identification

Clearly smaller and more compact than Whooper, with a shorter neck and a rounded, high forehead. The yellow bill base is small and rounded, covering less than half the bill and stopping before the nostril; the pattern differs on every bird. First-winters are dingy grey with a pink bill base.

Confusion species

On Whooper the yellow runs forward in a sharp wedge past the nostril and covers more than half the bill; on Bewick's the yellow patch is small, square or rounded and stays behind the nostril. Mute Swan is separated at once by its orange bill with a black knob and its arched, silent posture.

Habitat

Winters on damp grassland, sugar beet and potato residues and winter cereals, roosting on shallow lakes, creeks and border lakes. Breeds on arctic tundra in northern Russia beside pools and meandering rivers. Formerly tied to pondweed beds in shallow water, it now feeds mainly on farmland.

Range and movements

A breeder of the Russian tundra from the Kanin Peninsula east to the Lena. The north-west European population winters in the Netherlands, Britain, Ireland and northern Germany, with the Dutch polders and border lakes as its core. In Spain it is an exceptional vagrant with only a handful of records.

• Winter
• Passage
• dark = core range, pale = thinly spread

Where and when to look

Come in November and December to the Ooijpolder, the Lauwersmeer, De Wieden or the Flevo polders. Check roost lakes at first light, then follow flocks out to the beet fields; late afternoon light shows the bill patterns best. Take time over every individual bill, since each one is different.

Conservation status

The north-west European population has declined markedly since the 1990s. Poor breeding success on the tundra, illegal shooting and lead poisoning along the flyway, collisions with power lines and wind turbines, and a short-stopping of the wintering range eastwards under milder winters all contribute.