Common eider

Voice

In display the male gives a startled, almost human a-ooh-hoo that carries far over water and is one of the great sounds of the Wadden Sea. The female croaks low, korr-korr-korr. Heard mainly from January to April from displaying parties along the coast.

Identification

The male is white above and black below, with a green nape patch, a black cap and a rosy flush on the breast. The female is warm brown with dense black barring that makes her invisible among seaweed. Both show the flat bill profile; males need three years to reach full plumage and pass through piebald stages on the way.

Confusion species

Females and young are confused with the rare King Eider and with young Common Scoter. The long, straight forehead-to-bill line settles Common Eider; King Eider has a shorter profile with an S-shaped feathering border. The dense barring separates females from plain brown scoters.

Habitat

Shallow coastal water over hard bottoms with shellfish beds: tidal inlets, mussel banks, harbour moles, groynes and sheltered bays. Breeds colonially in dune vegetation, under creeping willow or elder scrub on the islands. Dives for mussels, cockles and crabs and swallows them whole.

Range and movements

A circumpolar breeder of northern coasts, in Europe from Iceland and Norway to the Wadden Sea. The Netherlands holds one of the southernmost breeding populations, concentrated on Vlieland, Terschelling and Texel. In Spain it is very rare, with occasional birds along the Cantabrian coast.

• Resident
• Breeding (summer)
• Winter
• Passage
• dark = core range, pale = thinly spread

Where and when to look

Go to a Wadden Sea dyke or the IJmuiden pier between February and April and listen for the display calls on a calm day. Come around high water, when birds feed close inshore along the groynes and males posture at one another with raised heads.

Conservation status

Listed globally as Near Threatened after declines in the Baltic. Dutch numbers crashed through shellfish fishery and food shortage, and recovery is slow. Drowning in nets, oil pollution, disturbance at colonies, fox predation on the mainland coast and disease all add pressure.