Medium-sized duck with extremely large breeding range across wetlands in whole North of Europe and Asia from Iceland to Bering Sea. Some decline but population still very large. Birds from large part of breeding range wintering along coasts of Denmark, Germany, Netherlands, France, Britain and Ireland and Italian Po Delta. Hunted in most of range, resulting in many recoveries. During winter inhabits large variety of open, wet areas. Herbivorous, with grasses dominating the diet. Forages nocturnally and rests during the day, but activity pattern influenced by degree of hunting.