This is the 9071st most frequent Japanese word.
渡り鳥
Migratory bird.
In this sentence, 渡り鳥 refers to actual migratory birds, emphasizing their natural behavior.
渡り鳥は季節に応じて移動します。
Migratory birds move according to the seasons.
渡り鳥 is metaphorically used here to compare someone who frequently moves or travels to a migratory bird.
彼はまるで渡り鳥のように各地を旅している。
He travels around various places like a migratory bird.
渡り鳥 again refers to the actual birds, but now in the context of bird-watching as a leisure activity.