Introduction
The Bronze-tailed Thornbill (Chalcostigma heteropogon) is a small high-altitude hummingbird of the northern Andes. It occurs in páramo and adjacent high-Andean habitats from western Venezuela through the Eastern Andes of Colombia. Its bronzy plumage, short bill and, in males, iridescent green throat make it a distinctive bird of the mountain shrublands and frailejón landscapes.
Physical Description
The Bronze-tailed Thornbill is a small hummingbird measuring approximately 10–13 centimetres in length. It has a short, straight bill, a bronzy green back, a reddish-bronze rump and a long, slightly forked bronze or bronzy-red tail.
The male has a dark crown and face, a glossy green throat and a small violet or pink mark at the lower edge of the throat. A pale buff or whitish collar may contrast with the darker bronzy underparts. The female is generally duller and lacks the male’s prominent iridescent throat pattern and pink chest mark. Her throat is paler, with less extensive green gloss, and her tail is usually shorter.
The combination of a short bill, bronzy body, long metallic tail and the male’s green-and-pink throat is useful for identification in the field.
Range and Habitat
The species is found in the high Andes of western Venezuela and northeastern Colombia, extending south through the Eastern Andes to Cundinamarca. It is not endemic to a single country, although much of its known distribution lies in Colombia.
The Bronze-tailed Thornbill usually occupies páramo, subpáramo and nearby high-Andean vegetation at roughly 2,900–4,000 metres above sea level. It favours open, rocky slopes, low shrubs, frailejón vegetation, grassy páramo, ravines with ferns and bromeliads, and the edges of stunted woodland, including areas with Polylepis. It is also associated with ecotones between páramo and dwarf or high-Andean forest.
These habitats can be cold, exposed and subject to rapid changes in weather. The species’ compact body, agile flight and ability to feed close to the ground are adaptations suited to this demanding environment.
Where to See This Species
Chingaza National Natural Park, Cundinamarca, Colombia
Chingaza supports páramo and high-Andean forest between approximately 3,100 and 4,020 metres, and the Bronze-tailed Thornbill is documented within the park. It is particularly worth looking for in frailejón páramo, shrub-rich slopes and high-elevation trails, where it may visit small flowers close to the ground. Access conditions, trail openings and booking requirements should be checked with the park authority before travelling.
Nearby accommodation: Guasca and La Calera are practical gateway areas with hotels, guest houses and rural accommodation, while camping and other authorised options may be available subject to park regulations.
El Cocuy National Natural Park, Boyacá, Colombia
The species has been recorded in the park’s high-elevation páramo, including the Páramo del Valle de Lagunillas at approximately 3,300–4,000 metres. Rocky páramo slopes, low shrubs and flowering plants provide suitable places to search, although the altitude and weather can make birding demanding. Visitors must follow the park’s access rules and use authorised routes and services.
Nearby accommodation: El Cocuy and Güicán are the principal gateway settlements, with hotels, guest houses, rural lodges and other visitor accommodation.
Behaviour and Diet
The Bronze-tailed Thornbill is usually seen alone. It forages low in the vegetation, moving rapidly between flowers and sometimes clinging briefly to a flower while feeding. It may defend a productive patch of flowers from other hummingbirds rather than gathering in large groups.
Its diet is based mainly on nectar from high-Andean plants. Recorded or regularly associated food plants include frailejones and flowers from families such as Ericaceae and Geraniaceae, as well as shrubs including Hesperomeles, Osteomeles, Rubus, Brachyotum and Bartsia. Small insects and spiders are also taken, providing additional protein and nutrients.
The species is regarded as resident rather than a long-distance migrant, although local movements may occur in response to flowering conditions, weather and changes in food availability. Detailed information about its breeding season and nesting biology remains limited. As in other hummingbirds, the female is expected to undertake nest building, incubation and most or all care of the young, but precise details should be treated cautiously unless supported by local observations.
Identification Tips
- Look for a small hummingbird with a short, straight bill and a relatively long bronzy tail.
- The male’s glossy green throat and small violet or pink mark at the base of the throat are the strongest field marks.
- The back is bronzy green, while the rump and tail may appear reddish bronze in good light.
- Females are less colourful and lack the male’s conspicuous throat pattern, so they may appear mostly dark above with a paler throat.
- Search low shrubs, frailejones, rocky slopes and páramo edges rather than concentrating only on tall flowering trees.
- The Bronze-tailed Thornbill can be confused with other high-Andean thornbills and small hummingbirds. The combination of its short bill, bronzy tail, dark head and the male’s green throat with a pink or violet lower mark helps separate it from species with longer bills, different tail colours or more extensive facial markings.
Conservation Status
The Bronze-tailed Thornbill is currently classified as Least Concern by BirdLife International. This category indicates that it is not presently considered globally threatened, but it does not mean that its habitat is secure.
Potential pressures include the conversion and degradation of páramo and high-Andean vegetation through agriculture, grazing, burning, mining, infrastructure development and other land-use changes. Climate change may also alter the distribution of páramo plants and flowering periods, with possible consequences for a hummingbird that depends on high-elevation habitats and seasonal nectar resources.
Protecting páramo, subpáramo and high-Andean forest, maintaining ecological connections between protected areas, limiting damaging land use and improving knowledge of the species’ population and breeding biology are important conservation measures.
Frequently Asked Questions
Where does the Bronze-tailed Thornbill live?
It lives in high-elevation páramo, subpáramo, shrubland and nearby high-Andean woodland from western Venezuela through the Eastern Andes of Colombia, as far south as Cundinamarca.
What does the Bronze-tailed Thornbill eat?
It feeds mainly on nectar from páramo and high-Andean flowers. It also takes small insects and spiders, especially when additional protein is needed.
How can the male be identified?
The male has a bronzy-green back, a long bronzy tail, a dark head, a glossy green throat and a small violet or pink mark near the lower edge of the throat.
Is the Bronze-tailed Thornbill endemic to Colombia?
No. It occurs mainly in Colombia but also reaches western Venezuela, particularly the Tamá region. It is therefore best described as a northern Andean species rather than a species endemic to Colombia.
Is the Bronze-tailed Thornbill a migratory bird?
It is generally considered resident. Local movements may occur when birds follow flowering resources or respond to changing conditions in high-elevation habitats, but it is not known as a long-distance migrant.
Where is it easiest to see this species?
Documented viewing locations include Chingaza National Natural Park and El Cocuy National Natural Park in Colombia. The best chances are in open páramo, frailejón vegetation, rocky shrubland and high-Andean forest edges at suitable elevations.
References
- BirdLife International
- Parques Nacionales Naturales de Colombia
- Gobernación de Cundinamarca
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