The Smew is the smallest representative of the Mergus genus. It measures 40 cm in length, 62 cm in wingspan, and 500-950 g in weight. There is marked sexual dimorphism especially in the winter. The white plumage of the male has a black mask and thin black lines on its body. The female is grey with a brown head. The bill is short with teeth which together with the hook at the end of the bill are efficient in catching slippery fish. It swims and dives well. It can take off directly from water without speeding. Its wing strokes are very fast. When it lands on water, it swoops and slows down its flight at the last moment.
Except during the hatching period the Smew lives in small groups. Smews are social and can live in a group with other ducks.
Distribution and Habitat
The Smew breeds in the northern areas of the Scandinavian Peninsula and Asia. It winters in the rest of Europe, including Bulgaria, the southern areas of Asia- in China, Japan, and Iran. It inhabits lakes and rivers in the tundra and taiga. In Bulgaria it is found mostly in lakes by the Danube river and Black Sea coastline.
The Smew eats predominantly animal food, small invertebrates, fish up to 6 cm in length, water insects, and plants take a small portion of its diet. It usually searches for food in shallow waters during the day. When feeding it dives up to 30 m and spends from 15 to 30 seconds under water.
The Smew is a monogamous bird. When the male performs its courtship dance, it circles around the female and raises its crest. It mates during March and April and nests in May and June by lakes surrounded with forest. It builds its nest in hollows in trees. The Smew lays from 5 to 11 cream-colored eggs which only the female incubates for about 26-28 days. The female takes care of the chicks alone. However, they hatch developed enough to move and feed independently.
According to IUCN its status is Least Concern, but in Bulgaria it is included in the list of birds that have priority for protection under Annex Ⅰ of the Birds Directive.