A typical forktail, with piebald plumage and long tail. Black head, upper back, chest and wings; white belly, rump, forecrown and wingbar; black and white tail and pale-pink legs. Inhabits shaded whitewater streams through montane rainforests, along which it perches on boulders and low-hanging branches. May overlap at mid-elevations with the very similar White-crowned Forktail which occurs in the lowlands, but Bornean has a longer tail and less extensive white on the head. Often detected by its vocalizations, a harsh buzzing whistle and high metallic whistles.