The Black-throated Brilliant (Heliodoxa schreibersii) is a medium-sized hummingbird found in tropical regions of Central and South America. With its iridescent emerald green plumage and vivid purple throat, it is considered one of the most colorful hummingbird species.
Introduction
The black-throated brilliant is a member of the hummingbird family Trochilidae. There are over 300 different hummingbird species, all restricted to the Americas. Hummingbirds are among the smallest birds in the world, with most species measuring only 3-5 inches long. Despite their diminutive size, hummingbirds have remarkably high metabolisms and heart rates to support the energy demands of hovering flight and nectar-feeding. Their name refers to the characteristic hum made by their rapidly beating wings.
The black-throated brilliant occurs in tropical forest and woodland habitats from southern Mexico to Bolivia. There are four recognized subspecies across this range, with some variation in the extent of purple gorget feathers on the throat. Like other hummingbirds, the black-throated brilliant feeds primarily on nectar from flowers using its specialized long bill. It also consumes small insects for essential proteins.
Description
The black-throated brilliant is unmistakable in appearance. The male has iridescent green upperparts and crown, with a brilliant purple gorget (throat patch) bordered below with fuzzy white breast feathers. The underparts are grayish-white with green spotting on the flanks. The long bill is straight and black. Females are similar, but less vibrantly colored on the throat and upperparts. Juveniles appear duller gray-green above with little or no purple on throat.
An average adult black-throated brilliant reaches lengths of 7 to 9 cm (3 to 3.5 in) and weighs 5 to 7 grams (0.2 oz). The wingspan is approximately 10 cm (4 in). As with all hummingbirds, there is remarkable diversity in plumage and gorget color across various populations and subspecies. The nominate race H. s. schreibersii from Costa Rica to Panama has the most extensive purple gorget in adult males.
Distribution and Habitat
The black-throated brilliant is found from southeastern Mexico through Central America into tropical South America. Its range extends through Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica and Panama into northern Colombia and Venezuela. Isolated populations occur in Ecuador, Peru, and Bolivia.
This species inhabits tropical evergreen forest, gallery forest, plantations, and parks from sea level up to 2500 m elevation. It appears to prefer humid lowland and foothill forest habitats. The black-throated brilliant is strongly associated with flowers and flowering trees.
Diet and Feeding
Like all hummingbirds, the black-throated brilliant feeds on plant nectar and tiny insects. Its specialized tubular tongue allows it to lick nectar out of flowers. Preferred nectar sources include plants from the Heliconia genus and various ornamental flowers. The long decurved bill is adapted for accessing nectar at the base of long tubular corolla flowers.
The black-throated brilliant supplements its diet with small insects like gnats, flies, beetles, and spiders. It often hawks flying insects, catching them in mid-air. Insects provide essential amino acids not found in nectar. This species prefers to feed from flowers high up in the forest canopy but will visit lower flowers and feeders.
Unique Behaviors
The black-throated brilliant exhibits some interesting behavioral adaptations related to its nectar-feeding habits:
– Trap-Lining: Individuals establish and regularly visit favorite nectar-producing flowers in a repeated circuit or “trap-line.” This helps ensure an efficient and reliable food supply.
– Nectar Robbing: Hummingbirds often cheat by piercing holes at the base of long tubed flowers to access nectar, avoiding pollination. The black-throated brilliant engages readily in “nectar robbing.”
– Aggressiveness: Males actively compete for access to nectar sources and exhibit aggressive displays like wing-waving and chasing intruders.
– Sunning: The black-throated brilliant engages in “sunning” by orienting its body perpendicular to sun-rays and spreading feathers. This behavior may serve thermoregulatory purposes.
– Pendant Nests: Females build small cup-shaped nests out of plant materials, spider silk, and lichens which hang suspended from branches.
Reproduction and Breeding
The breeding season of the black-throated brilliant corresponds with the wet season from May to August in Central America. Courtship displays involve aerial chases and dives by the male. Nests are constructed by the female on downward sloping branches 10-20 feet above ground.
The tiny nest is only about 2.5 inches wide and often well-camouflaged with lichens covering the outside. It is built out of plant down, cobwebs, and moss bound with spider silk. The female lays just two small white eggs. She incubates the eggs alone for about 15-19 days.
Chicks hatch with eyes closed and almost no feathers. The female alone provides care and feeds the chicks with regurgitated insects and nectar. After 20-26 days, the juveniles fledge and leave the nest. The female may reuse the same pendant nest for consecutive broods. Little is known about lifespan and mating habits beyond the breeding season.
Threats and Conservation
With its broad distribution across Central and South America, the black-throated brilliant remains relatively common. Its tolerance of disturbed forest habitats helps it persist across a range of protected to unprotected areas. However, habitat loss from deforestation poses threats, especially for isolated populations.
Partners in Flight estimates a global breeding population of 50,000 to 500,000 individuals. But some localized declines have been noted, including in Costa Rica. The species is currently evaluated as Least Concern on the IUCN Red List. Protected reserves across its range and planting flower gardens help maintain habitat for this beautiful hummingbird. More surveys and monitoring are needed to detect population trends.
Summary
With its vibrant iridescent plumage, specialized feeding adaptations, and aerial agility, the black-throated brilliant hummingbird has captivated bird enthusiasts across the Americas. This medium-sized tropical species exhibits remarkable adaptations for nectar-feeding including trap-lining, pendant nest building, sunning behaviors, and aggression at flowers. Maintaining humid forest habitats with abundant nectar sources will be key to preserving populations of this exotic hummingbird into the future. Though broadly distributed, increased habitat protection and monitoring efforts may be needed to ensure the black-throated brilliant continues to brighten tropical forests with its dazzling colors.