The eider's nest is built close to the sea and is lined with the celebrated eiderdown, plucked from the female's breast. This soft and warm lining has long been harvested for filling pillows and quilts, but in more recent years has been largely replaced by down from domestic farm-geese and synthetic alternatives. Although true eiderdown pillows or quilts are now a rarity, eiderdown harvesting continues and is sustainable, as it can be done after the ducklings leave the nest with no harm to the birds.
The Common Eider is characterized by its bulky shape and large, wedge-shaped bill. The male is unmistakable, with its black and white plumage and green nape. The female is a brown bird, but can still be readily distinguished from all ducks, except other eider-species, on the basis of size and head shape. This duck's call is a pleasant "ah-ooo." The species is often readily approachable.
This species dives for crustaceans and molluscs, with mussels being a favored food. The Eider will eat mussels by swallowing them whole; the shells are then crushed in their stomachs and excreted. When eating a crab the Eider will remove all of its claws and legs and then eat the body in a similar fashion.
It is abundant, with populations of about 1.5-2 million birds in both North America and Europe, and also large but unknown numbers in eastern Siberia (HBW).
A particularly famous colony of eiders lives on the Farne Islands in Northumberland, England. These birds were the subject of one of the first ever bird protection laws, established by Saint Cuthbert in the year 676. About 1,000 pairs still nest there every year.