Scaly-Sided Merganser

chinese merganser


Scaly-sided mergansers typically forage in rivers in small groups of up to three birds. They always feed into the current, in order to take advantage of the clearer water upstream. At night, they roost together in vegetation along riverbanks. Their nesting season takes place during the spring and summer seasons, from late March to October. During the winter, they fly south to various destinations—mainly in central and southern China—in flocks of up to 20 birds. These birds are shy and vigilant at all times, and tend to fly upstream when threatened or disturbed.


Scaly-sided mergansers forage in crevices and in the gravel lining riverbeds for stoneflies, shrimp, crayfish, beetles, and fish fry. Their long, thin, serrated, and hooked beaks are well adapted for catching their fast-moving prey.

Life Cycle

Scaly-sided mergansers live in mated pairs. Females make their nests in riverside tree holes (or nest-boxes), lined with down and grass. They will produce up to 15 ducklings (though more commonly, 6–8), which leave the nest after four or five days. The juveniles congregate in groups with one female, and fledge by 8 weeks of age.

Population Status & Threats

The scaly-sided merganser is listed as endangered by the IUCN Red List, with populations hovering between an estimated 1,000 and 2,500 individuals, and falling. The decline is due to habitat destruction, pollution, illegal hunting, and human disturbance of the sea ducks’ breeding territory.

WCS Conservation Efforts

Scaly-sided merganser populations are rapidly deteriorating. By successfully breeding them at the Central Park Zoo, we are working to ensure a future for this species as a whole.