Red-breasted merganser

Red-breasted Merganser female

©Amy Lewis

Red-breasted Merganser male

©Amy Lewis

Red-breasted merganser

Scientific name: Mergus serrator
The streamlined red-breasted merganser is a handsome bird and a great fisher - its long, serrated bill helps it to catch and hold its slippery fish prey. It is most commonly spotted around the coast in winter.

Species information


Length: 50-60cm
Wingspan: 78cm
Weight: 1.1kg
Average lifespan: est. 9 years

Conservation status

Classified in the UK as Green under the Birds of Conservation Concern 4: the Red List for Birds (2015).

When to see

July to March


The red-breasted merganser is a medium-sized duck and a member of a group called the 'sawbills' because of their long, narrow bills with saw-like 'teeth' which are good for gripping fish. A long, streamlined bird, it is perfectly shaped for swimming after fish. red-breasted mergansers are gregarious birds, forming flocks of hundreds in winter.

How to identify

The red-breasted merganser is a white diving duck. It can be distinguished from the Goosander by its thinner bill, grey sides, reddish-brown breast and crest of green feathers on its head.


Nests on lakes and rivers in the north and west of the UK. A common winter visitor to coastal waters.

Did you know?

Apart from the goosander (known in North America as the 'common merganser'), there are three other extant forms of merganser: the hooded merganser which nests in North America; the scaly-sided merganser, which is a rare bird of China, Japan and Korea; and the Brazilian merganser, which is one of the most threatened wildfowl in the world with only 250 birds living in the wild.

How people can help

The Wildlife Trusts work closely with fishermen, farmers and landowners to ensure that our wildlife is both protected and provides benefits for people. By working together, we can create Living Landscapes: networks of habitats stretching across town and country that allow wildlife to move about freely and people to enjoy nature. Support this greener vision for the future by joining your local Wildlife Trust.