Common merganser

Voice

Usually silent. In display the male gives a curious twanging, purring krro-krraa that suggests a distant frog, while the female answers with a hard, short karr karr. Mainly in February and March, when small parties of males swim around a female with their heads raised.

Identification

Large, long-bodied and low in the water, with a thin red hook-tipped bill. The drake is creamy white flushed pink on breast and flanks, with a glossy dark green head lacking an obvious crest and a black back. The female has a chestnut head with a short shaggy crest, a white chin patch and a sharp border between brown neck and grey breast. Immatures resemble the female.

Confusion species

Red-breasted Merganser is the mirror species. On females the head-to-neck border decides it: clean-cut with a white chin on Goosander, softly blurred and without white on Red-breasted. The drake is white-breasted against rusty streaked, and smooth-headed rather than double-spiked.

Habitat

Clear, fish-rich fresh water: large lakes, reservoirs, fast rivers and deep gravel pits, moving to brackish water only in hard frost. Breeds in tree holes and nest boxes along wooded rivers and lakes. Dives after fish, often in groups that herd a shoal together.

Range and movements

Breeds across northern and central Europe and along the mountain rivers of the Alps; a few pairs now nest in tree holes in the Netherlands. Large numbers winter on the IJsselmeer, the border lakes and the main rivers. In Spain it is a scarce winter visitor in the north, with a small breeding stock in the Pyrenees.

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

Where and when to look

December to February, early in the morning along the IJsselmeer, the border lakes or the Waal, when the birds fish actively before recreation starts. As frost sets in they concentrate on the last open water at locks and weirs, and those flocks are worth checking for Smew and Red-breasted Merganser.

Conservation status

The European population is stable to increasing and the species is spreading south-west. Locally the loss of old hollow trees along rivers, disturbance by recreation and illegal persecution at fish farms depress numbers. Drowning in gill nets plays a part on fish-rich waters.