noun
smew
A species of duck (Mergellus albellus). The name is usually written in katakana.
冬になると、ミコアイサが湖にやって来る。
In winter, smews come to the lake.
The name likely derives from 巫女 (miko, shrine maiden) and 秋沙 (aisa, merganser), referring to the bird's plumage pattern resembling a miko's attire, but the exact origin is uncertain.