Medium-sized confusing flycatcher. Male is beautifully colored, with deep blue upperparts, orange throat and breast, and white belly. Note dark face and electric blue highlight on the forehead. Female is duller, and differs with range: mainland and Javan birds have a grayish head, gray-brown wings, rufous tail, and orangish underparts; Bornean birds are darker brown above as well as darker orange below. Very similar to closely-related Large Blue Flycatcher: note marginally smaller bill without a noticeable hooked tip, less contrastingly pale throat, and darker legs. Male Hill Blue Flycatcher has more orange on the throat and a dark blue rump. Breeds in hilly and montane broadleaf thickets, often in areas with dense undergrowth; migratory birds winter at lower altitudes. Song mixes melodious warbling and whistling notes with harsh, rasping ones. Calls are a loud “chak” or “tak,” reminiscent of stones tapping.