The Swallow-tailed Hummingbird, scientifically known as Eupetomena macroura, is a striking member of the hummingbird family, Trochilidae. This species is notable for its long, deeply forked tail, which resembles that of a swallow and gives rise to both its common and scientific names—the latter meaning "large-tailed." With a total length of 15–17 cm, nearly half of which is the tail, and a weight of up to 9 g, it is a relatively large hummingbird. Its plumage is a dazzling iridescent green, complemented by a blue head, upper chest, tail, and vent.
The Swallow-tailed Hummingbird can be identified by its brilliant iridescent green plumage, blue head, and the characteristic long, deeply forked tail. It has a slightly decurved medium-long black bill. Males and females are similar in appearance, though females are slightly smaller and duller. Immature birds resemble females but have duller and more brownish-tinged heads.
This hummingbird is found in a variety of semi-open habitats, including gardens and parks within cities. It is most common among savanna-like vegetation and is generally a species of lowlands, occurring up to 1,500 meters in elevation.
The Swallow-tailed Hummingbird is primarily distributed in the Caatinga and Cerrado of Brazil, with its range extending to parts of northern and eastern Bolivia, and northern Paraguay. It is also found in coastal regions from French Guiana to Santa Catarina, Brazil.
The Swallow-tailed Hummingbird is known for its aggressive defense of rich food sources. It is dominant over other hummingbird species and will even attack much larger birds when perched. This species is not a true migrant, but some populations may move short distances during the dry winter months.
Its vocalizations include relatively loud "psek" notes and weaker twitters. When excited or alarmed, it emits a "tik" call.
Breeding behaviors can be observed almost year-round. The male performs courtship displays, including hovering in front of the female and engaging in aerial chases. The nest is a cup-shaped structure lined with soft plant fibers and camouflaged with lichen and mosses. The female alone cares for the eggs and young.
The Swallow-tailed Hummingbird is often unmistakable but may occasionally be confused with the male Violet-capped Woodnymph, which has only a blue cap, with the rest of the head being green.
This hummingbird primarily feeds on nectar from flowers of various families, including Fabaceae and Bromeliaceae, and will also hawk for insects. It forages from ground level to treetops and is attracted to hummingbird feeders in urban areas.
The Swallow-tailed Hummingbird is classified as Least Concern by the IUCN. It was once frequently exported for the cage bird trade but is now protected under CITES Appendix II, and trade is restricted.