Name: Scaly-sided Merganser
Scientific name: Mergus squamatus
Conservation status: IUCN - Endangered

The Scaly-sided Merganser is a duck species of a very small population, endemic to the East Asian-Australasian Flyway. It is therefore listed as Endangered under IUCN Red List. Scaly-sided Merganser Task Force was officially endorsed by EAAFP as a species Task Force (SsM TF) under Anatidae Working Group at EAAFP MoP5 in December 2010.


Their body size is between 52-62 cm. Both sexes have scaly-patterned feathers on sides and flanks.  They has crest of wispy elongated feathers, which is longer in male. Their beak is long and thin with serrated edge, bright red with yellow tip. Their legs are reddish-orange.

Adult males have a black-glossy green head, neck, and scapulars with black upperpart on the back, while females have brown head and are grey-coloured on the back.

Distribution range

*This map was produced by EAAFP Scaly-sided Merganser Task Force and EAAFP Secretariat.

Breeding grounds: breeds primarily in South East Russia, North-east China, and DPR Korea

Passage: South-east Russia, China, DPR Korea, Japan

Wintering grounds central and southern China, RO Korea


Scaly-sided Merganser reeding in tree holes © Bishui Nature Reserve, China

It breeds in well-forested mountainous clear flowing rivers, nest in tree holes. In non-breeding season, it inhabits lakes, reservoirs and mountainous rivers, also feeds along large rivers, estuaries, and the sea but predominately confined to freshwater habitat. It has low tolerant to human disturbance.

Population estimate

The number of individuals is estimated to be between 3,600 and 6,800 individuals in total, with 2400 – 4500 mature individuals.

Main threats

Habitat loss due to deforestation in breeding habitats and habitat degradation resulting from damming, dredging and water management in non-breeding habitats. Pollution and human disturbance are also impacting the population.

How you can help

  • Join surveys of Scaly-sided Merganser as volunteers organized by bird watching societies and scientists
  • Sustainable management of the sites where Scaly-sided Merganser use, help to plant trees
  • Help to promote the conservation of Scaly-sided Merganser
  • Support building artificial nests for Scaly-sided Merganser
  • Join EAAFP Scaly-sided Merganser Task Force
  • Donate and support EAAFP’s work

Learn more about Scaly-sided Merganser


Click [here] to download the Scaly-sided Merganser Factsheet. All Copyrights Reserved.