The Ferruginous Duck (Aythya nyroca) is a medium-sized diving duck.
Their breeding habitat is marshes and lakes with a metre or more water depth. These ducks breed in southern and eastern Europe and southern and western Asia. They are somewhat migratory, and winter further south and into north Africa.
The adult male is a rich chestnut colour with a darker back and a yellow eye. The pure white undertail helps to distinguish this species from the somewhat similar Tufted Duck. The female is similar but duller, and with a dark eye.
These are gregarious birds, forming large flocks in winter, often mixed with other diving ducks, such as Tufted Ducks and Pochards.
These birds feed mainly by diving or dabbling. They eat aquatic plants with some molluscs, aquatic insects and small fish. They often feed at night, and will upend (dabble) for food as well as the more characteristic diving.
These are gregarious ducks, mainly found on fresh water or on estuaries, though the Greater Scaup becomes marine during the northern winter.
Diving ducks do not walk as well on land as the dabbling ducks; their legs tend to be placed further back on their bodies help propel them when underwater.
Seaducks commonly found in coastal areas such as the Long-tailed Duck (formerly known in the US as Oldsquaw), scoters, goldeneyes and eiders are also sometimes colloquially referred to in North America as diving ducks because they also feed by diving.