Horornis diphone canturians

The Japanese bush warbler, known in Japanese as uguisu, is an Asian passerine more often heard than seen. It is olive-brown above and tends toward dusky colours below. In summer it ranges from low hills to high mountains, preferring bamboo thickets and black pine trees (Wikipedia, general species account).

Its distinctive breeding song can be heard throughout much of Japan from the start of spring, and in haiku and renga the uguisu is one of the seasonal words that signify early spring. The source covers the species as a whole and does not describe the continental form in China (Wikipedia, general species account).