The common eider (pronounced /ˈaɪ.dər/) (Somateria mollissima), also called St. Cuthbert's duck or Cuddy's duck, is a large (50–71 cm or 20–28 in in body length) sea-duck that is distributed over the northern coasts of Europe, North America and eastern Siberia. It breeds in Arctic and some northern temperate regions, but winters somewhat farther south in temperate zones, when it can form large flocks on coastal waters. It can fly at speeds up to 113 km/h (70 mph).