The Japanese Paradise-flycatcher (Terpsiphone atrocaudata), also called the Black Paradise-flycatcher, is a medium-sized passerine bird. It was previously classified with the Old World flycatcher family Muscicapidae, but the paradise-flycatchers, monarch flycatchers and Australasian fantails are now normally grouped with the drongos in the family Dicruridae, which has most of its members in Australasia and tropical southern Asia.
The Japanese Paradise-flycatcher is mainly migratory and breeds in shady mature deciduous or evergreen broadleaf forest of Japan (southern Honshu, Shikoku, Kyushu and the Nansei Shoto islands), South Korea, Taiwan (including Lanyu island) and the far north Philippines. It is a non-breeding visitor to mainland China, Hong Kong, Thailand, Laos, Vietnam, Philippines, Malaysia, Singapore, and Sumatra, Indonesia.
There are three subspecies, the nominate T. a. atrocaudata which breeds through most of Japanese/Korean range, T. a. illex which is resident in the Ryukyu Islands, and T. a. periophthalmica restricted to Lanyu Island off southeast Taiwan.
The Japanese Paradise-flycatcher is similar in appearance to the Asian Paradise Flycatcher but slightly smaller. Mature males have a black hood with a purplish-blue gloss which shades into blackish-grey on the chest. The underparts are off-white to white. The mantle, back, wings and rump are plain dark chestnut. The tail has extremely long black central feathers, which are shorter in immature males. Unlike the Asian Paradise Flycatcher there is no white morph. The female resembles the male but is duller and darker brown on the chestnut areas. It has black legs and feet, a large black eye with a blue eye-ring, and a short blue bill.
The song is rendered in Japanese as tsuki-hi-hoshi, hoi-hoi-hoi, which translates to Moon-Sun-Stars and gives the Japanese name of the bird ??????? (???) san?ch? (literally, bird of three lights, ie moon, sun, star, from san three + k? lights + ch? bird).
A recent survey detected a steep decline in part of the Japanese breeding population which has presumably occurred because of forest loss and degradation in its winter range.