The Green-throated Mountaingem (Lampornis viridipallens) is a medium-sized hummingbird found in mountainous regions of Costa Rica and western Panama. With its vibrant green throat and coppery-bronze body, it is one of the most striking hummingbirds in Central America.
Description
The adult male Green-throated Mountaingem has a brilliant metallic golden-green throat and upper breast that contrasts sharply with its otherwise coppery-bronze plumage. The bronze coloring extends from the lower breast down through the belly and undertail coverts. The upperparts are also golden bronze, including the crown, back, rump and uppertail coverts. The wings are dusky blackish-brown. The long bill is straight and black. Females are similar to males, but the throat is pale greyish-white instead of metallic green. Juveniles resemble adult females but with buffy edges to the feathers on the upperparts.
These medium-sized hummingbirds reach lengths of 10-12 cm (4-4.75 in) and weigh 5-7 grams (0.2-0.25 oz). The wingspan is approximately 6 cm (2.5 in).
Habitat and Distribution
The Green-throated Mountaingem inhabits cloud forests and woodland edges at elevations of 1200-3000 m in the highlands of Costa Rica and western Panama. Its breeding range extends along the Cordillera de Talamanca and Cordillera Central in Costa Rica, and the Cordillera de Talamanca in Panama.
Outside of the breeding season, this species can sometimes be found at lower elevations down to around 500 m. It occurs in areas where flowering plants and arthropod prey are abundant, including forest edges, semi-open areas, and gardens.
Diet
Like all hummingbirds, the Green-throated Mountaingem feeds on floral nectar and small arthropods. Its long, slender bill is adapted for probing into flowers and accessing nectar. This species favors tubular flowering plants in the genera Datura, Drymonia, Heliconia, and others. It also hawks small insects in flight, gleans insects from leaves and branches, and feeds on spider webs. Aided by its short legs and feet, the mountaingem can hover precisely in front of flowers while extracting nectar with its extensible tongue.
Behavior
Green-throated Mountaingems are solitary and territorial, defending flower-rich feeding territories from intruders. Males perform elaborate courtship displays, flying in U-shaped or J-shaped patterns to impress females. These energetic displays involve repeated dive-climbs and chases.
Vocalizations include sharp chip notes used in aggressive interactions with other hummingbirds. Territorial males also produce buzzy trills during courtship displays. The wings beat at around 20 beats per second, producing a high-pitched humming created by the rapid beating.
Reproduction
The breeding season for this mountaingem ranges from February to May in Costa Rica and western Panama. Males court females by performing courtship displays within their territories. Once paired, the female builds a small cup nest out of plant down and spider webs, attached to a vertical branch usually 3-15 m above ground. She incubates the two white eggs alone for 15-19 days before they hatch. Nestlings fledge at approximately 20-26 days old. Females may raise two broods per season.
Conservation
The Green-throated Mountaingem is evaluated as a species of Least Concern on the IUCN Red List, with an estimated global extent of occurrence of 20,000 km2. Population trends appear to be stable, and no major threats to the species have been identified. The remote cloud forest habitats this species inhabits face some threats from logging and conversion to agricultural land uses like coffee plantations. However, a substantial portion of the range occurs in protected areas like Chirripó National Park in Costa Rica. As long as sufficient upland forest is conserved, the ongoing survival of this dazzling mountaingem is expected.
Fun Facts
– The Green-throated Mountaingem’s genus name Lampornis comes from the Greek lampron meaning “bright” and ornithos meaning “bird”. This is an apt description of these glittery hummingbirds.
– Males have special colorful throat feathers called gorgets that they can puff out and flatten. When courting females, they fluff out these eye-catching gorgets.
– Mountaingems have uniquely structured feathers containing pigments that produce their brilliant iridescent colors. The structure of the feathers refracts light.
– They have amazing flying skills and agility, capable of sustained hovering, sudden stops, backward flight, and vertical take-offs. Their wings turn a full 180 degrees during each beat.
– These hummingbirds enter a state of torpor at night to conserve energy. Their metabolic rate drops and body temperature decreases.
– Their long slender bills are perfectly adapted for accessing nectar from curve-shaped tropical flowers. An extendible tongue darts in and out up to 13 times per second.
– Predators like falcons sometimes ambush these hummingbirds in flight. Other predators include snakes and tree-climbing mammals.
In summary, the vibrant Green-throated Mountaingem is a tropical gem, flashing its iridescent colors through the cloud forests of Costa Rica and Panama. Conserving these fragile mountain ecosystems will ensure the continued survival of these energetic pollinators and their specialized plant partners. Their diminutive size and buzzing flight belie an adventurous spirit and remarkable life history.