Long-legged and short-tailed, this tiny bird moves rapidly and unseen through dark, dense undergrowth like a pint-sized shadow. Yellowish-green above and gray below, with a black line extending through the eye below a pale yellowish eyebrow. Slaty-bellied Tesia is extremely similar, but has a brighter yellowish crown, darker gray underparts, and no pale eyebrow. Gray-bellied breeds in mid- to high-elevation forest, sometimes descending into lower foothills in the winter. Forages in dense undergrowth, particularly near streams and fern or bamboo clusters. Listen for its song: a few clear, high, bell-like notes followed by a brief sputtering explosion of lower notes.