The RSPB: Red-breasted merganser

Red-breasted merganser

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Latin name

Mergus serrator

Family

Swans, ducks and geese (Anatidae)

Overview

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.

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

Fish

Estimated numbers

Europe	UK breeding*	UK wintering*	UK passage*
-	2,370 pairs	10,500 birds	-

* UK breeding is the number of pairs breeding annually. UK wintering is the number of individuals present from October to March. UK passage is the number of individuals passing through on migration in spring and/or autumn.

Distribution

Key

Please note that the map is only intended as a guide. It shows general distribution rather than detailed, localised populations.

Audio is from commercial recordings Bird Songs and Calls of Britain and Europe on 4 CDs or Bird Sounds of Europe & North-west Africa, copyright WildSounds & CEBA (www.wildsounds.com, (UK) +44 (0) 1263 741100)