The Glittering-bellied Emerald (Chlorostilbon lucidus) is a small hummingbird found in forest and woodland areas of Costa Rica, Panama, Colombia and Ecuador. With its glittering green belly and bright blue-green crown, this aptly named hummingbird lives up to its dazzling appearance.
The adult male Glittering-bellied Emerald has mostly golden green upperparts from its crown to tail. The crown and throat are a vibrant blue-green. The underparts are glittering golden green on the belly, with a grey-white breast band separating the belly from the green throat. The tail is golden olive-green with a black subterminal band. The female is similar, but has a paler belly and greener crown. The bill of both sexes is straight and black. Juveniles resemble adult females but with buff edges to the feathers.
This diminutive hummingbird reaches a length of 9-10 centimeters (3.5-4 inches) and weighs around 5 grams (0.18 ounces). The wingspan ranges from 5.1-5.7 cm (2-2.25 in). As with all hummingbirds, the wings flap at high frequencies audible to humans as an insect-like buzzing. The slender downcurved bill and specialized tongue allow the Glittering-bellied Emerald to feed on nectar from flowers.
Habitat and Range
The Glittering-bellied Emerald inhabits tropical wet and moist forests, forest edges, second growth woodland and semi-open areas with scattered trees at elevations up to 1500 meters. Its range extends from central Costa Rica through western Panama and onto the Pacific slopes of the Andes in southwestern Colombia and northwestern Ecuador.
There is limited information on seasonal movements for this species. It appears to undertake minor elevational migrations, moving to slightly higher elevations after breeding.
Diet and Feeding
Like all hummingbirds, the Glittering-bellied Emerald feeds on flower nectar and tiny insects such as gnats and aphids. The primary plants utilized include Inga, Calliandra, Psittacanthus, Drymonia, Costus, Heliconia and Erythrina species, as well as cultivated plants such as shrimp plants (Justicia spp.) and coral vine (Antigonon leptopus). The long, specialized tongue allows the bird to reach nectar that other animals cannot access.
The Glittering-bellied Emerald plays an important role as a pollinator for many plants within its range. As it feeds, pollen sticks to the feathers around its bill and head. When the bird visits the next flower, this pollen is deposited to help fertilization.
Reproduction and Life Cycle
The breeding season runs from April to July, coinciding with the wet season. Males are promiscuous and mate with multiple females. The female alone builds the nest, a small delicate cup constructed from plant down and spider webs on a thin horizontal branch, tree fern or palm frond. She lays two tiny white eggs that hatch after 15-19 days.
The female alone incubates the eggs and cares for the young. The chicks are born helpless, with closed eyes and no down. They develop quickly, able to leave the nest in 18-26 days. The young hummingbirds must then learn to feed and fly skillfully to survive. Adults feed on a variety of small arthropods to obtain the high protein needed by growing chicks.
Threats and Conservation Status
The Glittering-bellied Emerald is evaluated as Least Concern on the IUCN Red List (last assessed in 2016). The population appears stable within its relatively widespread range. Potential threats include habitat loss from logging and agriculture.
– The genus name Chlorostilbon comes from the Ancient Greek words chloros for green and stilbe for gleam or shine, an apt descriptor for this glittering green hummingbird.
– Males perform aerial displays during courtship as they rise up about 5 meters before diving back down close to a perched female. They produce a loud snapping sound with their tail feathers during these steep dives.
– A Glittering-bellied Emerald was once observed stealing nesting material from an active Chestnut-mandibled Toucan nest! The tiny hummingbird was apparently undaunted by the much larger toucan.
– These hummingbirds favor bright red nectar-producing flowers such as the African tulip tree. They aggressively chase away other visiting hummingbirds as they fiercely guard favorite nectar sources.
– The emerald green and blue-green iridescent plumage of the Glittering-bellied Emerald does not result from pigments, but is produced by the refraction of light through specialized feather structures. This structural coloration changes dependent on viewing angle.
In summary, the Glittering-bellied Emerald is a diminutive yet dazzling tropical hummingbird decorated in glittering emerald green. Though small in stature, it plays an integral role as a pollinator for the plants that provide its preferred nectar. This species can be found zipping through forests from Costa Rica to Ecuador, where keen observers may spot its glittering green belly or hear the snapping dive displays of breeding males. With adequate habitat protection, the Glittering-bellied Emerald should continue to gleam through the canopies of Central and South America.