Fairly little ecological information is available for this small hummingbird. Slender-tailed Woodstars are subordinate to other hummingbirds and inhabit shrubby slopes, thorny scrub, deciduous woodland, and thicket-filled ravines. They have notably quick wing beats and zoom around visiting high flowers. Males and females are bronzy green above with a short white stripe behind the eye. Males boast a reddish purple throat and white chest while females are mostly buffy below.