Introduction
The Black-thighed Puffleg (Eriocnemis derbyi) is a small Andean hummingbird found in Colombia and north-western Ecuador. It occupies humid mountain habitats, forest edges and shrubby highland landscapes, where its dark leg feathers and glittering green plumage provide distinctive field marks.
Physical Description
The Black-thighed Puffleg is approximately 10 centimetres long. Adult males are mainly shining golden-green, with vivid metallic green upper and undertail coverts, blackish legs and a deeply forked black tail. The dense feathering around the legs gives pufflegs their characteristic booted appearance, while the black thighs explain this species’ common name.
Females are less brightly coloured. They have paler, often whitish underparts marked with green spots, a subtle bluish tinge on the forehead and leg puffs that combine black with greyish-white feathering. Juveniles resemble females and generally lack the stronger colour and gloss of adult males.
The bill is straight and dark, and the tail is noticeably forked. In good light, the combination of metallic green plumage, black leg feathering and a forked tail is highly distinctive.
Range and Habitat
The species occurs along the Central Andes of Colombia, from Tolima southwards, and continues into north-western Ecuador as far as Imbabura Province. It is therefore near-endemic to Colombia and Ecuador rather than restricted to a single country.
Black-thighed Pufflegs are associated with humid montane forest edges, elfin woodland, shrubby ravines, bushy pasture and other relatively open highland habitats. They are recorded mainly between about 2,500 and 3,600 metres, and are most frequent above approximately 2,900 metres. The species can use disturbed and human-modified habitats when suitable flowering plants and cover remain available.
Its distribution is patchy, and local abundance can vary considerably between sites and seasons. Seasonal movements up and down the mountains have been reported, although the extent and regularity of these movements are not fully understood.
Where to See This Species
Los Nevados National Natural Park, Caldas, Risaralda, Quindío and Tolima, Colombia
Los Nevados National Natural Park and its surrounding high-elevation landscapes are among the better-documented places to look for the Black-thighed Puffleg. The species has been recorded in the park and in nearby Andean habitats, particularly around forest edges, shrubby slopes and transitions towards páramo. It is not guaranteed, so careful searching around flowering vegetation is advisable.
Nearby accommodation: Manizales is the main practical gateway, with hotels, guest houses and rural accommodation available in the surrounding coffee-region communities.
Tinamú Reserve, Caldas, Colombia
Tinamú Reserve is a publicly visitable private reserve in the Andean coffee region with forest, grassland and garden habitats. The Black-thighed Puffleg is documented on the reserve’s bird list, making it a realistic site for observing the species in a managed birding environment. Visitors should check access arrangements before travelling.
Nearby accommodation: Manizales and the surrounding rural coffee region provide hotels, guest houses, lodges and other accommodation suitable for visitors exploring the reserve.
Behaviour and Diet
The Black-thighed Puffleg is usually encountered alone or in pairs. Like other hummingbirds, it can hover while feeding and may defend productive flowering plants or a small feeding area from other hummingbirds.
Its diet consists primarily of nectar. Recorded food plants include low-growing flowering plants such as Fuchsia and members of the palm family. It also takes small insects, including insects caught in short aerial sallies, which provide an important source of protein.
Breeding information remains limited. The female is responsible for nest construction, incubation and care of the young. Two white eggs have been reported, but the full breeding season, incubation period and fledging period are not well established.
Identification Tips
- Look for a small, bright green hummingbird with a clearly forked black tail.
- The black feathering on the thighs and leg puffs is the most useful diagnostic feature.
- Adult males are more uniformly glossy and golden-green than females.
- Females show paler underparts with green spotting and less vivid overall colour.
- Search forest edges, shrubby ravines, bushy pasture and flowering plants at high elevations rather than dense, closed-canopy forest alone.
- The species can occur alongside other pufflegs, so leg-puff colour, the forked tail and the pattern of the female’s underparts should be checked carefully.
Conservation Status
The current BirdLife International listing places the Black-thighed Puffleg in the Least Concern category. Earlier sources and some regional accounts have treated it as Near Threatened, so conservation information should be interpreted with reference to the latest assessment.
Despite its current global category, the species has a restricted and fragmented Andean distribution. Habitat loss and degradation caused by agricultural expansion, infrastructure, mining and other land-use changes remain important concerns, especially where high-elevation forest edges and shrubby habitats are cleared or isolated. Protecting montane forests, páramo margins and naturally regenerating vegetation, together with maintaining habitat connectivity, can benefit this and other range-restricted hummingbirds.
Frequently Asked Questions
Where does the Black-thighed Puffleg live?
It lives in the Central Andes of Colombia and north-western Ecuador, mainly in humid montane forest edges, shrubby highland habitats, bushy pasture and elfin woodland.
What does the Black-thighed Puffleg look like?
It is a small metallic green hummingbird with a forked black tail and distinctive black feathering around the thighs and legs. Females have paler, spotted underparts than males.
How high does the Black-thighed Puffleg occur?
It is generally found between about 2,500 and 3,600 metres above sea level, with many records above approximately 2,900 metres.
What does the Black-thighed Puffleg eat?
It feeds mainly on nectar from flowering plants and supplements this diet with small insects caught during short aerial sallies.
Is the Black-thighed Puffleg migratory?
It is not known to undertake long-distance migration, but seasonal movements between different elevations have been reported.
Where is a good place to look for this species?
Los Nevados National Natural Park and Tinamú Reserve in Colombia are documented birding locations where the species may be found. Sightings are not guaranteed, so searching flowering plants and forest-edge habitats is recommended.
References
- BirdLife International
- IOC World Bird List
- Parques Nacionales Naturales de Colombia
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