Scaly-Sided Merganser

Mergus squamatus 

SSP Coordinator:

Chuck Cerbini, Bronx Zoo 

Vice Coordinator:

Adam Haynes, Toledo Zoo & Aquarium

The scaly-sided merganser (Mergus squamatus) is a rare diving duck classified as Endangered in the wild, with a small and declining population concentrated in eastern Asia, particularly China and the Russian Far East. It breeds along clear, fast-flowing rivers and streams bordered by mature forests, where it nests in tree cavities, and winters on larger rivers, lakes, and reservoirs with clean water. Scaly-sided mergansers are primarily carnivorous, feeding mainly on small fish, along with aquatic insects, crustaceans, and other invertebrates captured while diving. Ongoing threats such as river pollution, dam construction, deforestation, and human disturbance continue to impact this species, making the protection of intact river ecosystems essential for its survival.