Woodnymphs (Thalurania) are medium-sized hummingbirds with a slightly decurved, black bill; the males also have a noticeably forked tail, and glittering throat and belly. They inhabit the understory of humid lowland forest and in adjacent advanced second growth, and often are common. The Green-crowned Woodnymph is the representative of this genus that occurs from eastern Panama south to southwestern Ecuador. As the name implies, this is the only species of woodnymph in which the crown of the male is glittering green. Four subspecies of Green-crowned Woodnymph are recognized. The three northern subspecies all are very similar: the male has a green throat but a blue breast and belly, while the female has a gray throat and the belly is mixed dark gray and dark green. The southernmost subspecies, hypochlora of southwestern Ecuador, is very different, however: the male is entirely green below, while the underparts of the female are all pale gray.