Charming tiny bird, brightly-colored but difficult to see as it forages quietly in dense undergrowth. Olive-yellow above and dark gray below, with a dark line through the eye and a bright yellowish crown. The very similar Gray-bellied Tesia has a paler belly, a distinct yellowish eyebrow, and a darker greenish crown. Slaty-bellied breeds in foothill and montane forest and winters at lower elevations. Frequents dark damp areas, often near streams or fern beds. Song is a series of high thin whistles followed by a jumble of warbled notes, longer and more complex than Gray-bellied Tesia’s similar song. Gives sharp chirping call notes, as well as loud rattles.