|Whooper swans are a northern hemisphere swan, with a range from Iceland to beyond Japan.|
Hokkaido, Japan Whooper swans on Lake Kussharo at dawn. The warm waters of the volcanic lake are usually slow to ice over, making it a good wintering habitat. Whooper swans are a northern hemisphere swan, with a range from Iceland to beyond Japan. They breed on islands and beside lakes and slow-flowing rivers from mid-May, and also frequently inhabit estuaries, marshes and floodplains. Their diet consists predominantly of leaves, stems and roots of aquatic plants. Around October, the swans fly to more temperate areas for winter. One 1,280-kilometer-long migration route, from Iceland to Ireland, is possibly the longest sea crossing by any swan species.