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Conservation status: Green

These handsome diving ducks belong to the sawbill family, so called because of their long, serrated bills, used for catching fish. Their diet of fish such as salmon and trout has brought them into conflict with game fishermen. At home on both fresh- and saltwater, red-breasted mergansers are most commonly seen around the UK's coastline in winter. They are gregarious, forming flocks of several hundred in the autumn.



Latin name

Mergus serrator


Swans, ducks and geese (Anatidae)

Where to see them

The UK breeding population is concentrated in the north-west of Scotland, England and Wales, and in parts of N Ireland. RSPB reserves with red-breasted mergansers in winter include: Morecambe Bay, Lancs; Langstone Harbour, Hants; Exe Estuary, Devon; Arne, Dorset; Snettisham and Titchwell Marsh, Norfolk; Lough Foyle, Co Londonderry; Belfast Lough, Co Antrim; Culbin Sands, Highland; Udale Bay, Highland.

When to see them

UK birds start to flock on the coast from July, reaching a peak in December. Birds from N Europe also arrive in late autumn. They return to the breeding areas in March.

What they eat



EuropeUK breeding*UK wintering*UK passage*
-2,400 pairs9,000 birds-




Ruud van Beusekom, Xeno-canto

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