The Chestnut-breasted Coronet (Boissonneaua matthewsii) is a species of hummingbird found in the Andes mountains of South America. With its vibrant green and blue plumage and long, curved bill, this striking bird has captured the fascination of ornithologists and bird enthusiasts alike.
Introduction
The chestnut-breasted coronet is a mid-sized hummingbird, measuring around 11-12 cm in length. As its name suggests, the male has a bright rufous-chestnut colored breast which contrasts beautifully with its metallic green crown and throat. The female is similar but has green scaling on the chest rather than the solid rufous-chestnut coloration. Both sexes have a brilliant blue rump, uppertail coverts and central tail feathers. The curved bill is black and relatively long compared to other hummingbird species.
This species has a wide distribution along the Andes mountains from Venezuela to Bolivia. It occupies humid montane forest and elfin forest at elevations between 1500-3200 m. The chestnut-breasted coronet shows a preference for habitats with plenty of flowering plants and scrubby vegetation. It uses its specialized long bill to probe tubular flowers and feed on nectar.
Taxonomy and Naming
The chestnut-breasted coronet is placed in the hummingbird family Trochilidae and the subfamily Trochilinae. The genus name Boissonneaua is named in honor of the 19th century French physician and ornithologist Jules Boissonneau. The specific epithet matthewsii commemorates the British ornithologist and plant collector Matthew Mathews who collected the first specimen in Colombia.
This species has no recognized subspecies, but some authorities split it into a northern nominate subspecies B. m. matthewsii and a southern B. m. orientalis based on minor plumage differences between populations. Further research is needed to clarify the taxonomic status of regional populations.
Identification
The vibrant coloration and long curved bill of the male chestnut-breasted coronet makes it relatively straightforward to identify. The brilliant blue rump patch along with the chestnut breast band separated by metallic greenScaling are diagnostic features. Females lack the solid chestnut breast but retain the blue rump and rufous scaling on a green background. The throat may appear entirely green or with some blue-violet iridescence.
In areas of range overlap, the chestnut-breasted coronet could potentially be confused with other Boissonneaua hummingbirds such as the buff-tailed coronet. However, the buff-tailed has a buff-colored breast band rather than chestnut, green rather than blue rump, and a shorter bill. Females and young birds are more challenging to distinguish. The violet-throated starfrontlet is similar in size and shape, but has a violet throat patch and lacks the bold rufous breast band.
Distribution and Habitat
The chestnut-breasted coronet has an extensive distribution throughout montane forest habitats in the northern and central Andes. Its range extends over 2600 kilometers from western Venezuela south along the Andes through Colombia, Ecuador, Peru, and Bolivia.
This species mainly inhabits humid montane evergreen forest between 1500 to 3200 meters elevation. It also occupies edges, clearings, secondary growth, and elfin forest at higher elevations. The chestnut-breasted coronet prefers areas with an abundance of flowering plants and vegetation for perching. Proximity to streams is also beneficial as it occasionally gathers small insects from the water surface.
In Colombia, it occurs on both slopes of the Cordillera Central and Cordillera Oriental as well as the Santa Marta mountains and Sierra Nevada de Santa Marta. In Ecuador, it inhabits the Andes west and east of the Guayllabamba river basin. In Peru, its range spans the length of the Andes including sheltered valleys and ridge habitats. The southern limit is in northwestern Bolivia where it has been recorded in montane forests near La Paz.
Due to its extensive elevational range, the chestnut-breasted coronet may migrate seasonally to lower or higher elevations to follow the bloom of favored nectar plants. However, limited research has been conducted on migration patterns and precise elevational movements.
Physical Description
The chestnut-breasted coronet exhibits striking sexual dimorphism, with vibrant plumage in the male and more subtle coloration in the female.
Male: The crown and throat of the male are metallic bottle-green. The upper breast is brilliant rufous-chestnut forming a conspicuous breast band. The lower breast and belly are dark gray. The back is golden-green. The rump and uppertail coverts are a vivid light blue. The long central tail feathers are also bright blue, while the lateral feathers have white tips. The wings are mostly dusky with a faint violet-blue iridescence. The bill is long, slender and black. Total length is 11-12 cm with a wing length around 5.5 cm.
Female: The female has the same basic pattern but chestnut breast scaling rather than a solid band. The throat may appear entirely green or with some blue-violet iridescence. The back is golden-green with bronze-green mottling. The rump is light blue and the tail feathers have violet-blue central feathers with white lateral tips. The bill shape is identical to the male. Females average slightly smaller at 10-11.5 cm length.
Juveniles of both sexes resemble adult females but with buff feather edging, particularly on the rump. The bill appears slightly shorter. After their first molt, juvenile males begin to show some rufous chest scaling.
Behavior and Ecology
The chestnut-breasted coronet exhibits behavior typical of other hummingbirds. Males are highly territorial and use elaborate aerial displays and vocalizations to advertise breeding territories. Their courtship displays include repeated vertical ascents and dives up to 100 feet in the air, with the wings producing a distinctive popping or snapping sound through modified outer primary feathers.
Females build a small cup nest out of plant down, moss, and lichens on a descending vertical branch or in a sheltered site on a rock face. Two white eggs are laid and incubated by the female for 15-19 days. The chicks are fed by the female on small arthropods and nectar and fledge at around 20-26 days after hatching.
This species feeds primarily on nectar taken from a variety of brightly colored, tubular-shaped tropical flowers such as species in the Families Bromeliaceae, Ericaceae, and Gesneriaceae. It uses its specialized tongue with hair-like extensions to reach and lap up the nectar. The chestnut-breasted coronet supplements its diet with small insects including flies, wasps, and spiders.
A close relationship exists between hummingbirds and their nectar plants. As the birds feed, pollen is transferred on their heads from bloom to bloom, making them important pollinators. The coronet’s long bill allows it to access nectar from long, curved flowers that cannot be pollinated by other birds or insects. This helps maintain healthy plant reproduction and diversity within its montane ecosystem.
Due to their high metabolic rate, hummingbirds must feed frequently to meet their energy needs. Chestnut-breasted coronets aggressively defend feeding territories containing sufficient flower resources. Males display from strategic perches within their territories, using vocalizations and dramatic aerial displays to advertise territory ownership and deter rivals. Females may also defend flower resources while nesting.
This species appears to be primarily solitary, coming together only briefly for breeding purposes. However, some loose flocks have been observed migrating or feeding at favored nectar sources. Given the challenges of its mountain environment, social thermoregulation may provide energy and survival benefits in harsh conditions.
Conservation Status
The chestnut-breasted coronet is evaluated as Least Concern on the IUCN Red List of Threatened Species. Its extensive range and population are presumed stable and face no major widespread threats. However, some localized declines from habitat loss and fragmentation have been noted, mainly from deforestation.
This species has adapted reasonably well to secondary forest, forest edges, and degraded areas provided sufficient flowers remain for foraging. As montane forest specialist, remaining dependent on specific habitat resources, ongoing protection of its natural Andean forest ecosystems is an important conservation priority. Climate change impacts are poorly understood but may threaten populations at higher elevations.
Somewhat surprisingly, the striking coloration of this hummingbird has not led to extensive exploitation by the caged bird trade, likely due to the remote forest environments it inhabits. However, trapping pressure should continue to be monitored, especially as access to remaining untouched forest areas increases. Ecotourism focused responsibly on observing this and other Andean hummingbirds may offer an alternative incentive for protection.
Conclusion
With its vibrant plumage refracting iridescent greens, blues, and chestnuts, the chestnut-breasted coronet is truly one of South America’s avian gems. While superficially appearing delicate, this species exhibits remarkable adaptation to the humid forests and meadows of the rugged Andes mountains. As an integral pollinator for its specialized ecosystem, continued conservation should ensure the survival of this resident hummingbird across the length of its Andean home. Ongoing research can provide further insight into the behavior and ecology of this tropical highland specialist. For those lucky enough to glimpse the chestnut-breasted coronet darting through dappled Andean forests, it’s an encounter not soon forgotten.