Mergellus albellus (Linnaeus, 1758) SY SMEW. 2200
Family: Anseriformes > Anatidae

Smew, Graham Catley

Crisp black and white-coloured male and red-headed female Smew are winter visitors to UK lakes, reservoirs and coastal waters.

Smew begin arriving in the UK during October but have a prolonged period of movements throughout the winter and birds can arrive at any time in response to freezing conditions on their Continental wintering areas. The south-east of the UK receives the lion’s share but a few individuals do make it further west. Records are scarce in Scotland, Wales and Ireland.

The numbers of Smew wintering in the UK has fallen in recent years, possibly in response to milder conditions on the Continent, which maintain waterbodies free of ice for longer.


Smew identification is usually straightforward.

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Status and Trends

Population size and trends and patterns of distribution based on BTO surveys and atlases with data collected by BTO volunteers.


This species can be found on the following statutory and conservation listings and schedules.




The Smew's winter distribution map shows that they were recorded widely across lowland England, Scotland and Wales during 2007–11. There were also records from the Isle of Man and the Channel Islands, where they are scarce winter visitors.

Occupied 10-km squares in UK

European Distribution Map

European Breeding Bird Atlas 2



Smews are localised winter visitors, most often recorded in late winter when cold weather on the continent can push birds into southern Britain.

Weekly occurence of Smew from BirdTrack
Weekly occurrence patterns (shaded cells) and reporting rates (vertical bars) based on BirdTrack data. Reporting rates give the likelihood of encountering the species each week.


Information about movement and migration based on online bird portals (e.g. BirdTrack), Ringing schemes and tracking studies.


View a summary of recoveries in the Online Ringing Report.


Lifecycle and body size information about Smew, including statistics on nesting, eggs and lifespan based on BTO ringing and nest recording data.



Sample sizes are too small to report Biometrics for this species.

Feather measurements and photos on featherbase


For information in another language (where available) click on a linked name

Gaelic: Sìolta-bhreac
Welsh: Lleian Wen
Catalan: bec de serra petit
Czech: morcák malý
Danish: Lille Skallesluger
Dutch: Nonnetje
Estonian: väikekoskel e. pudukoskel
Finnish: uivelo
French: Harle piette
German: Zwergsäger
Hungarian: kis bukó
Icelandic: Hvítönd
Irish: Síolta Gheal
Italian: Pesciaiola
Latvian: maza gaura, duncka
Lithuanian: mažasis danciasnapis
Norwegian: Lappfiskand
Polish: bielaczek
Portuguese: merganso-pequeno
Slovak: potápac malý
Slovenian: mali žagar
Spanish: Serreta chica
Swedish: salskrake
Folkname: White Nun (m) Redhead (f)

Links to more information from

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