a large Eurasian and North American merganser, the male of which has a dark green head and whitish underside 秋沙鸭
Mergus merganser, family Anatidae. North American name: common merganser 拉丁名Mergus merganser,鸭科。北美名:普通秋沙鸭
语源
early 17th cent.: probably from goose + -ander as in dialect bergander 'shelduck' (the colouring of the male goosander resembling that of the shelduck)