Introduction
The Black-backed Thornbill (Ramphomicron dorsale) is a small hummingbird endemic to the Sierra Nevada de Santa Marta in northern Colombia. It belongs to the hummingbird family, Trochilidae, and is one of the restricted-range birds associated with the mountain range’s humid forests, forest edges and high-elevation vegetation. Its limited distribution and continuing habitat loss make it a species of conservation concern.
Physical Description
The Black-backed Thornbill is approximately 9–10 cm long and has a very short, slightly curved black bill. Its tail is deeply forked and dark purplish or blue-black, with pale tips on some outer feathers, especially in females.
Adult males are distinctive. The upperparts are predominantly black, sometimes showing greenish or bronzy sheen, while the throat has a brilliant green to green-gold gorget. The lower underparts are dusky or brownish with greenish tones, becoming paler towards the vent.
Females are less strongly marked. They have bronzy-green upperparts, bronzy or purplish upper-tail coverts, and whitish underparts marked with green on the throat and flanks. Their tails are less deeply forked than those of males and show pale tips on the outer feathers.
Reliable information on juvenile plumage and age-related changes is limited. The sexes are readily distinguished by the male’s dark back and brighter throat compared with the greener upperparts and paler, spotted underparts of the female.
Range and Habitat
The Black-backed Thornbill is endemic to Colombia and is restricted to the Sierra Nevada de Santa Marta, an isolated mountain massif on the Caribbean coast. It is a resident species rather than a long-distance migrant, although local movements may occur as birds respond to flowering plants and changing conditions at different elevations.
It has been recorded from roughly 2,000 m to the upper forest and páramo zone, with records approaching 4,500 m. The species uses humid montane forest, cloud-forest edges, elfin woodland, semi-open high-elevation vegetation and páramo. It may also visit flowering plants and feeders in suitable montane habitat.
The range is small and fragmented. Much of the remaining suitable habitat lies within protected areas, including the Sierra Nevada de Santa Marta National Natural Park and private conservation reserves, but forest clearance, burning, grazing and agricultural expansion continue to affect parts of the mountain range.
Where to See This Species
ProAves El Dorado Reserve, Magdalena, Colombia
The ProAves El Dorado Reserve is on Cerro Kennedy in the Sierra Nevada de Santa Marta, near Minca. The reserve protects high-elevation montane forest and is one of the best-documented wildlife-viewing sites for this endemic hummingbird. Black-backed Thornbills have been recorded at the reserve, including around its visitor facilities and flowering areas, although sightings are not guaranteed. Early morning searches of forest edges, clearings and flowering plants are most appropriate.
Nearby accommodation: The reserve itself offers lodge-style accommodation, while Minca and the wider Santa Marta area provide guest houses, lodges, hotels and self-catering options. Visitors should check current access arrangements before travelling.
Behaviour and Diet
The Black-backed Thornbill is generally encountered alone. Like other hummingbirds, it can hover while taking nectar and may move rapidly between flowering plants. It may forage at different levels of the vegetation, from lower forest growth to the canopy and open highland areas.
Nectar is the main energy source, and the bird’s short bill is suited to feeding from flowers with accessible nectar. Small insects and other arthropods are also likely to be important, particularly as a source of protein. Field accounts report insect-catching and gleaning behaviour, but detailed studies of the species’ diet remain limited.
Males may defend productive feeding areas and perform aerial or display flights, but the species’ breeding behaviour is not well documented. As in other hummingbirds, the female is expected to undertake nest construction, incubation and care of the young, while the male’s primary role is associated with courtship and territorial behaviour. Precise information on nesting dates, clutch size and incubation is not sufficiently established for a detailed species account.
Identification Tips
- Look for a very small hummingbird with a notably short, slightly curved bill.
- An adult male has a black or very dark back, a bright green to green-gold throat and a deeply forked dark tail.
- A female is greener above and whitish below, with green spotting on the throat and flanks and pale tips to the outer tail feathers.
- The species’ dark, forked tail and short bill are useful field marks when viewed in silhouette.
- In the Sierra Nevada de Santa Marta, compare it carefully with other small hummingbirds. The combination of the male’s black back, luminous throat and very short bill is distinctive, while the female’s green upperparts, pale spotted underparts and pale tail tips are important identification features.
Conservation Status
The Black-backed Thornbill is currently classified as Near Threatened on the IUCN Red List. It was reassessed from Endangered to Near Threatened in 2023, but this change does not mean that the species is secure. It remains restricted to a small mountain range and has a fragmented distribution.
The principal threats are the loss and degradation of montane forest through agricultural expansion, deforestation, burning, grazing and other forms of land-use change. Climate change may also alter the distribution of suitable high-elevation habitat and the timing or availability of flowering plants, although the species-specific effects are not yet fully understood.
Important conservation measures include protecting remaining forest, maintaining habitat connectivity, restoring degraded areas and supporting conservation reserves such as ProAves El Dorado. The Sierra Nevada de Santa Marta National Natural Park also protects substantial areas of the species’ mountain habitat, although access to some sectors is restricted and conditions may change.
Frequently Asked Questions
Where does the Black-backed Thornbill live?
It is endemic to the Sierra Nevada de Santa Marta in northern Colombia, where it inhabits humid montane forest, forest edges, elfin woodland and high-elevation páramo.
Is the Black-backed Thornbill a migratory bird?
It is regarded as a resident species. Local movements may occur between elevations or feeding areas, but it is not known for long-distance migration.
How can the Black-backed Thornbill be identified?
The male is recognised by its black back, bright green or green-gold throat and deeply forked dark tail. Females are greener above, pale below and marked with green on the throat and flanks.
What does the Black-backed Thornbill eat?
It feeds mainly on flower nectar and also takes small insects and other arthropods. Nectar provides energy, while animal prey supplies additional nutrients.
Where is the best place to look for this species?
The ProAves El Dorado Reserve near Minca is the most clearly documented publicly accessible wildlife-viewing venue for the species. Searches should concentrate on high-elevation forest edges, clearings, flowering plants and reserve feeders where present.
Is the Black-backed Thornbill threatened?
It is classified as Near Threatened. Its restricted range and continuing habitat loss make protection of the remaining forests of the Sierra Nevada de Santa Marta important for its long-term survival.
References
- BirdLife International
- IUCN Red List of Threatened Species
- International Ornithologists’ Union, IOC World Bird List
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