Several white-winged ducks were resting by the lake.

white-winged 是由形容词 white（白色的）和名词 wing（翅膀）加上后缀 -ed 组成的复合形容词。winged 表示"有翅膀的"，white-winged 合起来意思是"白翅膀的"，用来描述鸭子翅膀的颜色特征。