The Golden-crowned Emerald Hummingbird (Chlorostilbon auriceps) is a small hummingbird found in Central America, northern South America, and the Caribbean islands of Jamaica and Hispaniola. With its vibrant green plumage and distinct golden crown, it is one of the most striking members of the hummingbird family.
Description
The adult male golden-crowned emerald has brilliant emerald green upperparts and underparts, with a golden crown patch on the head. The crown patch is bordered by black lores and auriculars. The tail is forked and steel blue. Females lack the vibrant crown patch and have lighter underparts with white flecking on the throat. The bill of both sexes is long, thin and straight. Juveniles resemble adult females.
Males measure 8–9 cm in length and weigh around 3–4 g. Females are slightly larger at 9–10 cm with an average weight of 4–5 g. Wingspans range from 10–11 cm. As with all hummingbirds, the golden-crowned emerald has specialized wings that allow it to hover in midair and fly backwards or upside down. The wingbeat is around 70 beats per second.
Taxonomy and Systematics
The golden-crowned emerald is placed in the order Apodiformes, family Trochilidae. It is one of around 140 species in the genus Chlorostilbon. Its species name auriceps is derived from the Latin words aurum (“gold”) and ceps (“crowned head”).
Two subspecies are recognized:
– C. a. auriceps – From Costa Rica to western Panama
– C. a. mosquerai – Jamaica and Hispaniola
The two subspecies differ slightly in size and color, with C. a. mosquerai being smaller and having a more bronze-tinged crown patch. Some authorities elevate the Hispaniolan birds to a separate species C. melanorhynchus. More research is needed to clarify the taxonomic status of the Caribbean subspecies.
Distribution and Habitat
The golden-crowned emerald is found from southern Mexico through Central America into Colombia and Venezuela. The Caribbean subspecies C. a. mosquerai is found on Jamaica and Hispaniola.
This hummingbird inhabits a range of wooded habitats including semi-arid scrub, deciduous forest edges, coffee plantations, parks and gardens. It occupies a wide elevational range from sea level up to 5000 ft.
Feeding
Like all hummingbirds, the golden-crowned emerald feeds on nectar from flowers using its specialized long tongue. It favors flowers with red tubular blooms, inserting its bill deep inside to drink the nectar. Some favorite flower genera include Heliconia, Erythrina, Costus, Salvia and Hamelia.
Small insects such as spiders and flies are also gleaned from foliage and provide an essential source of protein. The bird uses its bill to snatch insects out of spider webs.
Courtship and Reproduction
Males are promiscuous and mate with multiple females in a season. Courtship involves aerial displays where the male flies in repeated arcs and dives to impress the female. If receptive she will perch and allow copulation.
The female alone builds the nest which is a small cup of plant fibers bound with spider webs. It is attached to a downward hanging leaf or frond up to 49 ft above ground. The average clutch is two tiny white eggs which are incubated by the female for 15-19 days.
The chicks are fed regurgitated food by the female and fledge after 20-28 days. The female continues to feed the young for a week or two after fledging. Golden-crowned emeralds face threats from nest predators like snakes and ants. Average lifespan in the wild is 3-5 years.
Migration
Northern and highland populations migrate altitudinally for the winter. Birds move to lower warmer elevations from September to November and return in February to April. In Costa Rica, golden-crowned emeralds migrate from highland nesting sites above 4900 ft down to lower elevations near sea level for the winter months.
Vocalizations
The call is a high-pitched staccato sounding like “chi-chip-chi” or “chit-it-it”. The call is given year round during foraging and interactions. Males sing to attract females during the breeding season, producing a rapid twittering trill.
Status and Conservation
The golden-crowned emerald has a very wide range and large total population. Partners in Flight estimates a global breeding population of over five million. Numbers today remain stable so the IUCN Red List categorizes this species as Least Concern.
Major threats include habitat loss from deforestation and urbanization. The Caribbean subspecies C. a. mosquerai has a much smaller and fragmented range which makes it more vulnerable. Providing nectar plants in gardens can help support urban populations of this dazzling hummingbird.
Fun Facts
– The emerald shimmer of the males led the Aztecs to believe these birds were messengers of the god Huitzilopochtli.
– To conserve energy, golden-crowned emeralds enter torpor at night by lowering their body temperature and metabolic rate.
– The species name “auriceps” means “golden-headed” in Latin.
– Their long bill allows golden-crowned emeralds to feed from specialized tubular blossoms. Many plants depend on these hummers for pollination.
– Golden-crowned emeralds have excellent memory and regularly return to feed from the same patch of flowers.
– The inverted flying skills of hummingbirds are essential for gaining access to nectar from hanging heliconia flowers.
With its glittering green plumage, the aptly named golden-crowned emerald is truly one of Central and South America’s most dazzling hummingbirds. As urbanization increases across its range, habitat provisions in parks and gardens can go a long way towards ensuring the future survival of this energetic and beautiful species.