Common Eiders were hunted intensively in the 1800s and the Atlantic populations almost died out. Subject to one of the earliest bird-protection laws in the UK, numbers have recovered and there are now more than two million individuals worldwide. They are still hunted for sport in the USA. They are susceptible to oil spills, declining prey and being caught in fishing nets.
Amazing Common Eiders
Common Eiders are the largest ducks in the northern hemisphere. Breeding males have very beautiful and striking plumage with bold patches of white, black and pale green. Outside the breeding season, males have plainer feathers and look similar to the drab-coloured females, which are brown with black bars. Common Eiders in the Pacific region have quite different markings and may be a distinct species.
To collect their invertebrate prey, Common Eiders dive to the sea floor. They swallow whole shellfish such as mussels and crush the tough shells in their stomachs.
From October to March, Common Eiders spend winter at sea. At other times of the year these birds breed in colonies of up to 3000 pairs in the northern parts of their range. Each bird returns to the same colony in which it hatched. Female Common Eiders lay up to 14 greenish eggs in a scrape in the ground, which is lined with soft feathers plucked from their breasts. These feathers, known as eiderdown, have long been used to stuff pillows and quilts. They are now harvested sustainably from old nests once the ducklings have left.
The ducklings are able to swim soon after hatching. Ducklings from unrelated broods often congregate in ‘creches’ that are watched over by their mothers and by non-breeding females.