© Copyright: Images: Jari Peltomäki, Kari Pihlaviita, Jouko Lehmuskallio, Jari Hiltunen, M. & W. von Wright: Svenska fåglar (Kansalliskirjasto, The National Library of Finland). Recording: Jan-Erik Bruun. All rights reserved.
- Name also: Common Eider
- Family: Waterfowl – Anatidae
- Appearance: Finland’s largest diving duck, the Eider is a heavily built sea duck, as large as a small goose. Head large and wedge-shaped, neck thick. Males mainly black and white in colouring, females mottled brown.
- Size: Length 60–70 cm, wingspan 95–105 cm, weight 1.2–2.6 kg.
- Nest: Sheltered by bushes, in a hollow on a rocky shore or a bank of washed up seaweed. Large amounts of down used to line nest.
- Breeding: 3–7 eggs laid in April, incubated by female for 25–32 days. Ducklings leave nest immediately after hatching and soon learn to find food for themselves, though they stay together as a brood near their mother until they learn to fly at the age of 9–10 weeks. Often several females will bring their broods together to form large nursery flocks.
- Distribution: Breeds throughout Finland’s coastal waters but scarcer in eastern Gulf of Finland and only occasionally breeds in the Bothnian Bay. Has declined in numbers lately. Finnish breeding population estimated at 50,000–130,000 pairs.
- Migration: Migrates by day. Most males fly south to Danish waters at the end of May or in early June to moult. Main autumn migration September–October, returning to Finnish waters in April–May. Winters in the Baltic Sea Proper and the North Sea, though some birds may stay in the Archipelago Sea.
- Diet: Mainly mussels.
- Calls: Males’ spring mating call a hollow dove-like “auo auuo”, females’ call a more goose-like “gok-gok-gok…”.
- Endangerment: Endangered, protected. Hunting is still permitted (in 2009 4,300 eiders were shot). Finland is home to about 40% of the EU’s breeding Eider population. Globally Near threatened.
Male Eiders in breeding plumage can be recognised from a long distance by their whitish backs and dark underparts, tails and wing feathers. They also have black caps, green patches on their necks, and pink-tinged whitish chests. Males shed their breeding plumage in June and grow their autumn plumage, which is a fairly uniform dark brown with a broad indistinct eye stripe and a large white wing patch.
Young male Eiders (in their second summer) resemble mature males in their non-breeding plumage, but have paler chests and lack the broad white wing patch. Females and juveniles are a uniform mottled brown. Their speculum wing panels are brown with a slight violet tinge, lined on both sides with white wing stripes. Juvenile Eiders are darker brown in the autumn and their eye stripes and other markings are less distinctive. Female and juvenile Eiders are most easily distinguished from similar species by the elongated wedges of brown feathers on the sides of their beaks that extend as far as their nostrils. Eiders’ legs are greenish yellow (males) or greenish grey (females). They have greenish beaks and brown irises.