Green Thorntail is a small, uncommon hummingbird that occurs from Costa Rica south to western Ecuador. Thorntails have a distinctive, bee-like flight. They typically forage at flowering canopy trees, and also glean insects from the under surfaces of large leaves in the canopy. Only the male has the long, deeply forked tail with very narrow tips to the outer rectrices. The tail of the female is short, but one of the most distinctive features of the female is a broad white malar stripe. Both sexes have a white band across the rump and a white flank patch; in most of its geographic range, it is the only hummingbird with a white rump band. Otherwise very little is known about the natural history of Green Thorntail.