The violet-capped woodnymph (Thalurania glaucopis) is a species of hummingbird in the Trochilidae family. It is found in forest (primarily humid), dense woodland, gardens and parks in south-eastern Brazil, eastern Paraguay, Uruguay, and far north-eastern Argentina (primarily Misiones Province). It is widespread and generally common, and therefore considered to be of Least Concern by BirdLife International (and consequently the IUCN). The male is distinctive, being overall green with a blue cap and deeply forked dark blue tail. It is occasionally confused with the swallow-tailed hummingbird. The female lacks the blue crown, has entirely greyish-white underparts, and a shorter, white-tipped tail.
Violet-capped Woodnymphs inhabit a wide range of habitats from untouched forests, to scrub, to suburban and city gardens. They gather nectar from both native and non-native flowers and also hunt for insects. During certain parts of the year, Violet-capped Woodnymphs migrate short distances. Males have a bluish violet cap and sparkle with dark green above and gold-green below. Females are dark greenish above and off-white below. During the breeding season, these woodnymphs adorn the outside of their nests with ferns and lichen.