Rare term for the lesser cuckoo (Cuculus poliocephalus). The more common name is 時鳥 (ほととぎす).
See also: ホトトギス
The term 時の鳥 sometimes appears in old texts as another name for the lesser cuckoo.
The kanji 時の鳥 literally mean 'bird of time', likely referring to the cuckoo's seasonal call. The reading ときのとり is a kun'yomi-based alternative to the more common ほととぎす.