The green-tailed goldenthroat hummingbird (Polytmus theresiae) is a small, strikingly colored hummingbird found in Costa Rica and western Panama. With its vibrant green and blue plumage and long forked tail, it is one of the most beautiful hummingbirds in Central America.
The green-tailed goldenthroat is a very small bird, measuring only 3-3.5 inches in length. As its name suggests, it has brilliant golden-green plumage on its throat. The male’s throat feathers shine iridescently in the sunlight. The rest of the head and neck are an intense velvety blue. The back and tail coverts are metallic green. The exceptionally long tail is deeply forked and steel blue. The underparts are white and the legs and feet are black. The long thin bill is straight and black. Females are similar to males but lack the iridescent throat patch and have white tips on the outer tail feathers. Juveniles resemble adult females but have buffy fringes on the throat, breast and flanks.
Distribution and Habitat
The green-tailed goldenthroat is found along the Pacific slope of Costa Rica and western Panama. Its natural habitats are humid montane forests and forest edges at elevations between 3000-9000 feet. It can also sometimes be found in gardens and secondary growth. It prefers areas with flowering plants and a dense understory. This species has a very small global distribution of less than 50,000 square km.
Like all hummingbirds, the green-tailed goldenthroat feeds on flower nectar and tiny insects such as gnats, mosquitoes and spiders. It uses its long, slender bill to extract nectar from a variety of brightly colored tubular flowers including lilies, fuchsias and mints. It also hawks small insects in flight or gleans them from leaves and twigs. Its fast metabolism requires it to consume over half its body weight in nectar each day.
The green-tailed goldenthroat is a solitary and timid bird, actively avoiding humans. It is most active in early morning and late afternoon. During the day it perches inconspicuously under cover, spending up to 85% of its time perched between feeding bouts. In flight it is swift, maneuverable and agile. During the breeding season, males perform aerial displays, flying in pendulum arcs up to 100 feet in the air. Their wingtips produce a loud buzzing and whistling sound during these displays.
The breeding season for this species runs from March to May. Males establish small territories centered around a prime nectar source and perform aerial displays to attract females. Once paired, the female builds a tiny cup-shaped nest out of plant down, lichen and moss, bound together with spiderwebs. She lines the nest with soft plant fibers and attaches it to a downward sloping fern or tree branch, 10-45 feet above ground. The female lays two tiny white eggs and incubates them alone for 15-19 days. The chicks hatch with their eyes closed and minimal down. They are fed regurgitated nectar and insects by the female and fledge in 18-23 days.
The green-tailed goldenthroat has a very limited range but is fairly common within that range. Its population trend appears to be stable and it is classified as Least Concern by the IUCN Red List. Potential threats include habitat loss from logging and conversion of forests to agriculture. Climate change may also impact hummingbird populations by causing shifts in flowering and nectar availability. Strict habitat protection will be important for the long-term survival of this species. Expanding protected areas and limiting deforestation within its range are conservation priorities. More research is needed on its precise habitat needs and responses to habitat fragmentation. With proper habitat conservation measures in place, the outlook for the green-tailed goldenthroat remains positive.
Overall, the beautiful green-tailed goldenthroat is a jewel of Central America’s cloud forests. Its glittering colors and energetic flight dazzle lucky observers. This delicate species serves as an important pollinator for mountain ecosystems. Protecting its specialized high elevation habitat will be crucial in ensuring the green-tailed goldenthroat continues to brighten cloud forests for generations to come.