A mother merganser and her chicks in the Changbaishan National Nature Reserve. [Photo by Zhao Wenbin/For China Daily]

Nesting boxes have been placed high in trees for Chinese mergan­sers in the Changbaishan National Nature Reserve. ZHUO YONGSHENG / FOR CHINA DAILY

In November, after the chicks have grown, most Chinese merganser families wing it south for the winter, returning to Changbaishan Mountain in April. The arduous migratory cycle can stretch over thousands of kilometers.

Chinese mergansers rest by a river in the Changbaishan National Natural Reserve. [Photo by Zhao Wenbin/For China Daily]

A female scaly­sided merganser and her chick sit at their nest in the

Piao Zhengji, an expert at Changbaishan National Nature Reserve. [Photo provided to China Daily]