Scaly-sided Merganser nestbox scheme reports latest results 03085e90-f050-4803-bcca-aa1529f73a73 Scaly-sided Merganser is one of the world's most beautiful ducks, yet it is also among the rarest. The species, which is classified as Endangered, has a very small population, which is suspected to be undergoing a continuing and rapid decline as a result of habitat loss, illegal hunting and disturbance. Although many birders see it on wintering grounds in the likes of South Korea and Japan, Scaly-sided Merganser breeds in the Russian Far East (85% of the population is in the Sikhote-Alin mountain range) and the far north-east of China. Here it favours pristine river valleys surrounded by primary forest, relying on the presence of natural cavities in mature trees in which to breed. However, logging has reduced the availability of suitable habitat across much of its range.