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 (for example, at Dungeness), 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 (AEWA) applies.
It is not considered threatened on the IUCN Red List, though its population is decreasing.
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 (for example, at Dungeness), 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 (AEWA) applies. It is not considered threatened on the IUCN Red List, though its population is decreasing.
Smew