The term smew has been used since the 17th century and is of uncertain origin. It is believed to be related to the Dutchsmient and the German Schmeiente or Schmünte, "wild duck." It is probably derived from smee, a dialectal term for a wild duck.
Description
The drake smew, with its 'cracked ice' and 'panda' appearance, is unmistakable, and looks very black-and-white in flight. The females and immature males are grey birds with chestnut foreheads and crowns, and can be confused at a distance with the ruddy duck; they are often known as "redhead" smew. It has oval white wing-patches in flight. The smew's bill has a hooked tip and serrated edges, which help it catch fish when it dives for them. The smew is long.
This species breeds in the northern taiga of Europe and the Palearctic. It needs trees for breeding. The smew lives on fish-rich lakes and slow rivers. As a migrant, it leaves its breeding areas and winters on sheltered coasts or inland lakes of the Baltic Sea, the Black Sea, northern Germany and the Low Countries, with a small number reaching Great Britain, mostly at regular sites. Vagrants have been recorded in North America. On lakes it prefers areas around the edges, often under small trees. The smew breeds in May and lays 6–9 cream-colored eggs. It nests in tree holes, such as old woodpecker nests. It is a shy bird and flushes easily when disturbed. The smew is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds applies. It is not considered threatened on the IUCN Red List, though its population is decreasing.
Fossil history
An unnamed fossil seaduck, known from a humerus found in the Middle Miocene Sajóvölgyi Formation of Mátraszõlõs, Hungary, was assigned to Mergus. However, the authors included the smew therein, and consequently, the bone is more properly assigned to Mergellus—especially as it was more similar to a smew's than to the Bucephala remains also found at the site. It is sometimes argued that the Mátraszõlõs fossil is too old to represent any of the modern seaduck genera, but apparently these were all well-distinct even back then. Subfossils from this species was also found in England indicate that the living species' range extended there a few hundred years ago.
