basic plumage

countable uncountable

The plumage of a bird following its first moult (or the first of a year)

Japanese Meaning

鳥が初めて換羽を経た後に生える羽毛、または年内初めの換羽後の羽毛

After the autumn moult, the young gull's basic plumage made it difficult to distinguish it from adult birds.

秋の換羽の後、若いカモメは初換羽後の羽衣により成鳥と見分けがつきにくかった。

Sense（1）

The plumage of a bird following its first moult (or the first of a year)

basic plumages

（ plural ）