The Golden-breasted Puffleg (Eriocnemis mosquera) is a species of hummingbird found exclusively in the Andes mountains of Colombia and Ecuador. Known for its vibrant plumage and restricted range, this species has become a major conservation priority in recent years.
The golden-breasted puffleg is a medium-sized hummingbird, measuring around 11-12 cm in length. The male has distinctive golden-bronze plumage on its underparts, for which the species is named. The upperparts are mostly covered in sparkling emerald green feathers. The female is slightly duller, with gray underparts rather than golden. The puffleg name refers to the distinctive white leg puffs or tufts present in both sexes.
This species is endemic to a small region of the Andes at altitudes between 2500-3500 meters. Its total global range covers around 15,000 square km in the departments of Cauca and Huila in Colombia and the provinces of Carchi and Sucumbíos in Ecuador. Within this region, the puffleg inhabits montane forest and paramo grasslands characterized by cold temperatures, frequent mist, and relatively high rainfall.
Due to its restricted range and declining population, the golden-breasted puffleg is classified as Endangered by the IUCN Red List. Habitat loss, climate change, and other threats have caused its numbers to dwindle to an estimated global population of only 1000-2500 mature individuals. Intensive conservation action will be required to protect the remaining populations and habitat of this range-restricted hummingbird.
Evolutionary History and Taxonomy
The golden-breasted puffleg belongs to the hummingbird family Trochilidae and the subfamily Trochilinae. Along with about 140 other species, it is placed in the genus Eriocnemis, which consists of other Andean puffleg hummingbirds. This genus evolved around 5 million years ago and radiated to occupy various montane niches in the Andes. The closest living relative of the golden-breasted puffleg is believed to be the colorfully named Black-thighed Puffleg, E. derbyi.
The golden-breasted puffleg was first scientifically described in 1913 by the British ornithologist C. Chubb, based on a specimen collected in southwest Colombia. For many decades it was considered a color variant of the more widespread Sapphire-vented Puffleg (E. luciani). More recently, morphological, vocal, and genetic studies have confirmed it as a valid species in its own right. Its scientific name mosquera honors the Colombian ornithologist Augusto José Ramírez Moreno.
No recognized subspecies of the golden-breasted puffleg are currently known. However, some minor differences in plumage brightness have been noted between populations on different mountain slopes, indicating a degree of localized variation.
Description and Identification
The golden-breasted puffleg’s vibrant plumage makes it essentially unmistakable within its limited range. No other Andean hummingbird matches its distinctive golden underparts combined with emerald green upperparts. Even the female can be readily identified by her gray underparts and white leg puffs.
In good lighting, the male’s throat and forehead may appear to glow brightly with a golden-orange iridescence. The tail is slightly forked and dark bronzy-purple. The bill of both sexes is mostly blackish but reddish at the base. The legs and feet are brownish-black. Juveniles somewhat resemble females but have buffy scalloping on the undersides and whiter leg puffs.
When observed up close, other subtle plumage details become noticeable. Small green spots fleck the golden breast. The emerald green back has a bronzy-gold wash. White tips adorn the outer tail feathers. While perched, the male often fans and fluffs out his spectacular flank plumes. The female lacks these distinctive flank ruffs.
This species could potentially be confused with the Sapphire-vented Puffleg, which inhabits some of the same mountains. The male Sapphire-vented has extensive sapphire blue underparts lacking golden tones, while the female has buff-colored underparts with white flecks. Hybridization occasionally occurs in areas where the two species’ ranges overlap. The Blue-throated Puffleg is another smaller puffleg of the high Andes, but it is easily separated by its white-bellied female and glittering blue throat patch on the male.
Voice and Sounds
One of the best ways to detect the presence of golden-breasted pufflegs is by their vocalizations. Both sexes produce a high, thin, whistled song atypical of most hummingbirds. Each song consists of a rapid series of 12-18 clear, slightly descending notes lasting 2-3 seconds in total. These high-pitched vocalizations carry well through the misty air of the mountains. Males sing from high perches within or at the edge of forest habitat. This advertising song is thought to function primarily in territorial defense against other males.
In addition to the song, golden-breasted pufflegs have a variety of call notes. Sharp chip or cheep notes are given in aggressive interactions or when alarmed. Some sounding like high-pitched tzeet sounds. Displaying males make a thin clicking sound with their outer tail feathers. Calls of perched birds help pinpoint their location within mossy forest understories.
Distribution and Habitat
The small global range of the golden-breasted puffleg is limited to the wet northern Andes mountains in southern Colombia and adjacent northern Ecuador. In Colombia, it occurs only in the departments of Cauca and Huila between about 2° to 3° north latitude. There are scattered records from three mountain complexes – Munchique, Guanacas-Puracé, and Las Hermosas. In Ecuador, populations are found on the east and west slopes of the Cordillera Oriental in Carchi and Sucumbíos provinces.
Throughout this zone the puffleg is found between elevations of 2500 and 3500 meters. It occurs mainly in forested habitats within this elevation band, most commonly in elfin forest or mossy forest with Chusquea bamboo understories. It also frequents adjacent Paramo grasslands habitats for feeding. Dwarf forest, forest edges, and second growth areas provide additional habitat. Ravines, streamsides, and roadsides lined with brush are regularly used.
Population and Conservation Status
The golden-breasted puffleg has a highly restricted distribution and specialized montane forest habitat. These factors make it vulnerable to extinction, especially in light of ongoing habitat loss and climate change. Intensive surveys in recent decades have revealed the population to be very small and fragmented. Total numbers are estimated at just 1000-2500 mature individuals, roughly equivalent to 1500-3500 total individuals.
Habitat conversion for agriculture, logging, and human settlement is the primary threat. Up to 90% of suitable habitat may already be lost in parts of its range. Parambo grasslands are also being degraded by grazing pressures and burning. Climate change poses a severe long-term threat by shifting cloud forests higher in elevation. Due to its limited dispersal abilities, the puffleg may be unable to sufficiently track these upward shifts in habitat.
As a result of population declines and habitat deterioration across its tiny range, the golden-breasted puffleg is considered Endangered by the IUCN Red List. Protecting remaining habitat and alleviating threats are urgent conservation priorities. Parts of its range occur in national parks like Munchique and Llanganates, but even these require more effective protection and management.
Ecology and Behavior
The golden-breasted puffleg, like all hummingbirds, has unique adaptations for hovering flight and nectar-feeding. It feeds through traplining by visiting a regular circuit of favored flower species. Primary nectar sources are in the Plantago, Escallonia, and Brachyotum plant genera. Some small arthropods are also gleaned as an important protein source. Foraging occurs mainly within forest understories but also in adjacent open areas.
Males display remarkable territorial behavior, vocally advertising from perches and aggressively chasing intruders. Courtship displays involve aerial flights and maneuvers. Nests are tiny cups of moss and lichen attached to vertical substrates. Females lay two white eggs that hatch after about 16-19 days. Incubation and rearing duties are performed exclusively by the female. Like many tropical hummingbirds, the puffleg appears to breed opportunistically almost year-round following rains.
This scarce species has been little-studied in the wild and many aspects of its biology remain unknown. Even basic natural history information on feeding, reproduction, and population densities are lacking. Telemetry studies of movements and home range size have not yet been conducted. Given its inherent vulnerabilities, a high priority for future research is better understanding its ability to disperse across fragmented habitats.
Importance to Ecosystems and Humans
As a highly specialized nectarivore and pollinator, the golden-breasted puffleg fills an important ecological role in its specialized cloud forest and paramo ecosystems. It is an integral contributor to plant pollination networks at certain elevations. Some plant species with red tubular flowers seem to be specifically adapted for pollination by this puffleg. Any declines or disappearance of this hummingbird would likely impact pollination chains and ecosystems.
For humans, this endangered species has value as a unique component of Neotropical biodiversity. It can serve as a regional flagship species to promote conservation of threatened Andean forests. Birdwatchers also travel from afar for a chance to observe the puffleg’s dazzling plumage and interesting behaviors. Nature tourism focused on the puffleg offers a sustainable development opportunity for local communities. But habitat protection efforts are needed to ensure the species persists long-term.
The golden-breasted puffleg’s exquisite beauty highlights the diversity of avian life, especially Andean hummingbirds. Yet its restricted range and Endangered status also make it a poster child for the plight of tropical montane species threatened by extinction. Concerted efforts to protect remaining populations and habitats will be critical to ensure this puffleg and other range-restricted species survive the coming century as suitable habitat shifts and disappears. With dedicated human commitment, the golden beauty of this puffleg can continue illuminating the misty forests it calls home.