Rare, poetic or classical name for the lesser cuckoo (Cuculus poliocephalus). In modern Japanese, the bird is almost always called ホトトギス.
See also: ホトトギス
In old waka poetry, 'nubatamadori' can refer to the lesser cuckoo.
The standard modern Japanese name for the lesser cuckoo. 射干玉鳥 is a rare, classical synonym.
The exact derivation is uncertain. The spelling 射干玉 is ateji, and the word likely originated as a poetic name for the bird, possibly related to the old makurakotoba ぬばたま (used for 'black' or 'night').