Red-breasted merganser

Voice

Silent away from display. Displaying males stretch the neck and give a soft, cat-like dje-djuu, females a harsh krrok-krrok. Given in April and May on estuaries and the Wadden Sea, and usually audible only in calm weather at close range.

Identification

Both sexes show a thin red hooked bill and a shaggy double crest that sticks out in all directions. The male has a green-black head, a white collar, a spotted rusty breast and grey flanks. The female is grey with a rufous head that fades gradually into the whitish throat, with no clean border.

Confusion species

Females are the classic pitfall against Goosander. On Red-breasted the rufous head blends softly into a dingy white throat and neck, while Goosander shows a sharp border and a well-defined white chin patch. Red-breasted is also slighter, with a thinner bill and a messier crest.

Habitat

Shallow salt and brackish water: tidal inlets, estuaries, harbours, lagoons and sheltered bays. Breeds on saltmarsh, dune islands and along clear northern rivers and lakes. The nest is tucked under bushes, driftwood or dense marram grass, often near tern colonies.

Range and movements

Breeds around the northern hemisphere from Iceland and Scotland to northern Russia, with a small Dutch population on the Wadden islands. Winters along most of the Atlantic seaboard. In Spain it winters sparsely in the Cantabrian rías, Galician bays and occasionally the Ebro delta.

• Resident
• Breeding (summer)
• Winter
• Passage
• Migration direction
• dark = core range, pale = thinly spread

Where and when to look

Watch from a sea wall or pier at a Wadden Sea inlet in November and December, two hours after high water when the current picks up. Birds fish actively in the channel then; look for diving ducks with a thin red bill and a flapping crest.

Conservation status

The European population is declining slightly. The main pressures are bycatch in set gill nets, oil pollution at sea, recreational disturbance of nesting islands and predation by fox and mustelids. The Dutch breeding population is small and fluctuating, while winter numbers are fairly stable.