When at sea the common scoter feeds mainly on small fish and invertebrates. In the freshwater breeding habitat it also takes insect larvae, fish eggs and the seeds of water plants (6). They dive to obtain their food, (6) and whilst submerged the wings are partially opened in order to stabilise themselves as they search for food on the bottom (4). Scoters start to pair up in winter. The nest is built on the ground amongst dense vegetation from grass, moss lichens and down (6). Between 6 and 8 buff-coloured eggs are laid between the end of May and late June; shortly after this the male leaves the female and joins other males before going to sea to moult. Soon after hatching the young are able to swim but do not fledge for another 45-50 days (2).