Black-breasted Puffleg**

Eriocnemis nigrivestis

Trochilidae - Hummingbirds

**Critically Endangered

The Black-breasted Puffleg is a critically endangered hummingbird endemic to northwestern Ecuador, with fewer than 250 individuals estimated to remain in the wild. It inhabits high-altitude cloud forests and shrubby ridgelines between 2,400 and 3,500 meters, primarily on the slopes of Volcán Pichincha, Atacazo, and the Cordillera de Toisán. This altitudinal migrant feeds on nectar from ericaceous plants and vines, and its survival is threatened by habitat fragmentation, climate change, and land conversion for agriculture. Once adopted as the emblem of Quito, the species now teeters on the edge of extinction, clinging to isolated patches of montane forest.

** Due to the Endangered status of this species, an in-depth report has been prepared below. All photos were taken by me on 26OCT2025 at Zuro Loma.

Section heading for Where Observed in Ecuador

Black-breasted Puffleg 26 Oct 2025 #1 Reserva Zuro Loma | EC-P

Section heading for About the Species in Ecuador

The Black-breasted Puffleg (Eriocnemis nigrivestis) in Ecuador: Distribution, Occurrence, Conservation, and Natural History

Introduction

The Black-breasted Puffleg (Eriocnemis nigrivestis) is a striking and enigmatic hummingbird, endemic to the high Andean forests of northwestern Ecuador. Known locally as the zamarrito pechinegro, this species is recognized for its distinctive white leg puffs and, in males, a deep black plumage with iridescent blue highlights. Despite its status as the official bird of Quito and its emblematic role in Ecuadorian conservation, the Black-breasted Puffleg remains one of the world’s rarest and most threatened hummingbirds. Its survival is imperiled by a combination of habitat loss, climate change, and ecological pressures, making it a focal species for conservation action and research in the Andean region.

This report provides a comprehensive, narrative-style field guide entry on the Black-breasted Puffleg in Ecuador, synthesizing the latest scientific findings and conservation assessments. It covers four key aspects: (1) distribution within Ecuador, including specific regions, elevations, and habitats; (2) occurrence patterns, such as seasonal movements, abundance, and detectability; (3) conservation status, including IUCN status, population estimates, threats, and conservation actions; and (4) natural history, including feeding behavior, breeding biology, and ecological interactions. The aim is to offer an in-depth, accessible resource suitable for field guides, educational materials, and conservation planning.

Distribution in Ecuador

Geographic Range and Specific Localities

The Black-breasted Puffleg is a strict Ecuadorian endemic, with its entire known range confined to the northwestern Andes. Historically, its distribution was thought to be extremely limited, but recent research has clarified the presence of at least two main subpopulations: one on the northwestern flanks of the Pichincha volcano (Pichincha Province) and another in the Cordillera de Toisán above the Intag valley (Imbabura and Esmeraldas Provinces).

The Pichincha subpopulation is the best studied and most frequently observed. It is centered on the ridge crests and upper slopes of the Pichincha volcano, west of Quito, and includes sites such as the Yanacocha Reserve, Verdecocha Reserve, and adjacent forest remnants. Notable localities within this area include Cerro Pugsi, Loma Gramalote, Loma Frutillas, and Hacienda La Merced de Nono. The Yanacocha Reserve, managed by Fundación Jocotoco, is particularly significant as it harbors the largest known protected population and serves as a focal point for research and ecotourism.

The Cordillera de Toisán subpopulation was rediscovered in 2006 after decades without confirmed records. This population inhabits the high ridges and slopes above the Intag valley, straddling the provinces of Imbabura and Esmeraldas. Key sites include Cayapachupa and the upper Cristopamba valley, within or adjacent to the Cotacachi-Cayapas Ecological Reserve. Fieldwork has confirmed the presence of the species in primary high-Andean wet forest and elfin forest at elevations above 3,100 meters.

There are also historical or unconfirmed records from other sites, such as Volcán Atacazo (southwest of Quito), Sachatamia Lodge (Pichincha), and the Intag valley itself. However, these records are either based on old museum specimens or isolated sightings, and the current status of the species in these areas remains uncertain.

Elevation Range

The Black-breasted Puffleg is a montane specialist, typically found at elevations between 1,700 and 3,500 meters above sea level. Most recent and reliable records are concentrated between 2,700 and 3,500 meters, with the species being most numerous at 2,850–3,500 meters during the non-breeding season and above 3,100 meters during the breeding season (November to February). Dispersing immatures have occasionally been observed as low as 1,700 meters, particularly during post-breeding movements or in years with unusual climatic conditions.

Habitat Types

The preferred habitats of the Black-breasted Puffleg are humid and wet cloud forests, especially high-Andean montane forests, elfin forests, and forest borders. Within these ecosystems, the species shows a marked preference for mature, relatively undisturbed forest tracts with a dense understory and abundant flowering shrubs. Ridge-crest elfin forests, characterized by stunted trees and a rich diversity of epiphytes and shrubs, are particularly important, especially in the Cordillera de Toisán and at sites like Verdecocha.

The species also utilizes shrubby forest borders, steep slopes with stunted vegetation, and, less frequently, the interior of taller montane forests and clearings. However, recent studies indicate that the Black-breasted Puffleg tends to avoid abrupt forest edges and highly disturbed habitats, likely due to increased physiological stress and reduced resource availability at these boundaries. Instead, it favors areas further from the forest edge, where microclimatic conditions are more stable and floral resources are more predictable.

In summary, the Black-breasted Puffleg’s distribution is highly localized and fragmented, restricted to a handful of sites in the northwestern Andes of Ecuador, with a strong association to high-elevation, humid montane forests and elfin forest habitats.

Occurrence Patterns: Abundance, Movements, and Detectability

Abundance and Population Structure

The Black-breasted Puffleg is exceptionally rare and localized. Even within suitable habitat, it is considered scarce, with only a few individuals typically observed during intensive surveys. At Yanacocha and Verdecocha, for example, a maximum of four individuals have been observed together during transect counts, and the estimated subpopulation at Pichincha volcano may number up to 80 individuals, equating to roughly 50 mature birds. The Cordillera de Toisán subpopulation is less well studied but may be of similar or slightly larger size, with recent surveys suggesting a density of 2–4 individuals per hectare in optimal habitat.

The global population is tentatively estimated at 100–150 mature individuals, divided between two main subpopulations (Pichincha and Toisán), with no evidence that all individuals are concentrated in a single location. The population is believed to be declining, with ongoing habitat loss and fragmentation as the primary drivers.

Seasonal Movements and Altitudinal Migration

The Black-breasted Puffleg exhibits seasonal altitudinal movements, a behavior common among Andean hummingbirds. Historically, the species was thought to be most numerous between 2,400 and 3,050 meters from April to September (the non-breeding season), and to move above 3,100 meters during the breeding season from November to February. However, recent observations indicate that these patterns may be more complex or variable than previously believed, with records of the species at a range of elevations throughout the year and some evidence of shifts in response to local flowering phenology and climatic conditions.

Altitudinal migration in this species appears to be closely linked to the seasonal availability of key nectar plants, particularly those that flower at different elevations at different times of the year. During the rainy season, when breeding occurs, the birds tend to remain at higher elevations, possibly to take advantage of peak flowering of certain shrubs and reduced competition. In the drier months, they may descend to lower elevations where alternative food sources are available.

Detectability and Survey Methods

Detecting the Black-breasted Puffleg in the field is challenging due to its rarity, elusive behavior, and preference for dense, often inaccessible habitats. The species is generally silent, with no distinctive vocalizations, although it may emit a soft, metallic "tseet tseet tseet" when disturbed or in flight. Juveniles may produce a high-pitched chirp when begging for food.

Standardized transect surveys and audiovisual censuses are the primary methods used to monitor the species. These involve walking fixed routes through suitable habitat and recording all individuals seen or heard within a defined distance (typically 20 meters on either side of the transect). Given the low density of the species, repeated surveys and long observation periods are necessary to obtain reliable data.

In recent years, time-lapse camera traps placed at flowering plants have proven effective for documenting feeding visits and presence, providing valuable information on occurrence patterns and plant-hummingbird interactions. These cameras can operate continuously for days or weeks, capturing rare and otherwise easily missed visits by the Black-breasted Puffleg.

Despite these efforts, the species remains difficult to detect, and its true abundance and distribution may be underestimated. Survey records are often biased toward accessible sites with higher observer effort, such as Yanacocha Reserve, and there is a need for expanded surveys in less-studied areas, particularly in the Cordillera de Toisán and other potential habitats.

Historical Records and Changes Over Time

Historically, the Black-breasted Puffleg was known from a broader range, with museum specimens collected from elevations as low as 2,440 meters and as high as 4,725 meters. However, most recent records are concentrated between 2,700 and 3,500 meters, and the species appears to have disappeared from many former localities, likely due to habitat loss and fragmentation.

The rediscovery of the species in the Cordillera de Toisán in 2006 expanded the known range and provided hope for additional, as yet undocumented, populations. Nevertheless, the overall trend is one of range contraction and increasing isolation of subpopulations, underscoring the urgency of conservation action.

Conservation Status

IUCN Red List Assessment

The Black-breasted Puffleg is currently classified as Endangered on the IUCN Red List, having previously been listed as Critically Endangered for several decades. The most recent assessment (2020) is based on the following criteria:

Extremely small and fragmented range (Extent of Occurrence estimated at 590 km², Area of Occupancy at 100 km²)
Very small and declining population (estimated 100–150 mature individuals)
Continuing decline in habitat extent, quality, and population size
Severe fragmentation and presence at only 2–5 locations

The species is also listed on CITES Appendix II, providing some international protection against trade.

Population Estimates and Trends

As noted above, the global population is estimated at 100–150 mature individuals, with two main subpopulations (Pichincha and Toisán) and possibly a few additional, unconfirmed localities. The population is believed to be declining, with a suspected reduction of 10–19% over the past decade, primarily due to ongoing habitat loss and degradation.

Population estimates are based on intensive field surveys, camera trap data, and extrapolation from known densities in accessible areas. At Yanacocha-Verdecocha, up to 20 individuals have been observed, with the Pichincha subpopulation possibly numbering up to 80 individuals. The Toisán subpopulation may be of similar or slightly larger size, but data are limited due to the remoteness and inaccessibility of much of the area.

Major Threats

The Black-breasted Puffleg faces a suite of severe and interacting threats, including:

Habitat Loss and Fragmentation: Over 93% of suitable habitat within the species’ historical range has been destroyed, with 97% lost in Pichincha Province alone. The main drivers are deforestation for timber and charcoal, conversion of forest to cattle pastures and potato farms, and expansion of the agricultural frontier.
Charcoal Production: The felling of Polylepis and other high-Andean trees for charcoal remains a significant threat, both for local use and commercial sale in Quito. Charcoal production is particularly damaging on ridge crests, which are prime habitat for the species.
Agriculture and Livestock Grazing: The establishment of cattle pastures and potato fields has led to the loss and degradation of forest, especially on relatively flat ridge crests and upper slopes.
Fires: Both natural and human-induced fires are common during the dry season, destroying large tracts of forest and preventing regeneration. Fires are often set to clear land for agriculture or to maintain pastures.
Infrastructure Development: The construction of the Oleoducto de Crudos Pesados (OCP) oil pipeline and associated roads has resulted in direct habitat destruction and increased access for further deforestation.
Mining: In the Cordillera de Toisán, copper mining concessions and land invasions threaten remaining forest, particularly within the Cotacachi-Cayapas Ecological Reserve.
Climate Change: Rising temperatures are expected to shift suitable habitat upslope, potentially pushing the species above the current treeline and reducing the area of available habitat. Climate change may also alter flowering phenology and increase competition with other hummingbirds, such as the Gorgeted Sunangel (Heliangelus strophianus).
Competition and Ecological Interactions: The expansion of the Gorgeted Sunangel into higher elevations may increase competition for resources, further limiting the Black-breasted Puffleg’s niche.

Conservation Actions and Protected Areas

A range of conservation actions have been implemented or proposed to address these threats:

Protected Areas: The Yanacocha Reserve (c. 1,100 ha), managed by Fundación Jocotoco, is the largest and most important protected area for the species, safeguarding key habitat on the Pichincha volcano.The adjacent Verdecocha Reserve (1,200 ha) and the Bosque Protector Mindo-Nambillo (19,200 ha) provide additional protection. In the Cordillera de Toisán, the Cotacachi-Cayapas Ecological Reserve (243,638 ha) encompasses much of the remaining habitat, although enforcement is limited and threats persist.
Habitat Restoration: Reforestation and habitat enrichment projects have been initiated, including the planting of native cloud forest species and key nectar plants such as Palicourea fuchsioides and Macleania rupestris. These efforts aim to restore degraded areas, enhance habitat connectivity, and provide critical resources for the species.
Community Engagement: Conservation organizations, notably Aves y Conservación and Fundación Jocotoco, have worked with local communities to promote sustainable land use, reduce charcoal production, and implement fire prevention measures. Environmental education programs, workshops, and the distribution of educational materials have raised awareness of the species and its plight.
Research and Monitoring: Standardized monitoring protocols, including transect surveys and camera traps, have been developed to track population trends and ecological requirements. Ongoing research focuses on plant-hummingbird interactions, habitat use, and the impacts of land-use change and climate change.
Policy and Advocacy: The Black-breasted Puffleg was declared the emblematic bird of Quito in 2005, raising its profile and fostering political support for conservation. Efforts are underway to strengthen legal protection, improve reserve management, and lobby against mining and other destructive activities in key habitats.

Despite these initiatives, major challenges remain, including insufficient enforcement of protected area regulations, ongoing habitat loss outside reserves, and the need for greater funding and capacity for restoration and monitoring.

Conservation Data Summary Table

The table above summarizes the key conservation data for the Black-breasted Puffleg, highlighting the critical status of the species, the small and fragmented population, and the main threats and conservation responses.

Natural History: Feeding, Breeding, and Ecological Interactions

Morphology and Identification

The Black-breasted Puffleg is a small to medium-sized hummingbird (8–9 cm in length), with pronounced sexual dimorphism. The male is distinctive, with entirely blackish upperparts, a violet-blue throat and undertail coverts, dark blue uppertail coverts, and a forked steel-blue tail. The most striking feature is the dense white feathering around the legs (“pufflegs”), which gives the species its common name. The female is bronze-green above, bluish-green on the rump and uppertail coverts, golden-green below with a pale blue chin, and shares the white leg puffs and forked tail. Juveniles resemble adults but are duller, with some red-orange on the lower bill.

Feeding Ecology and Key Nectar Plants

Like most hummingbirds, the Black-breasted Puffleg is primarily nectarivorous, supplementing its diet with small insects and spiders for protein, especially during the breeding season. The species feeds on a wide variety of ornithophilous (bird-adapted) flowers, but recent research has identified a strong preference for certain key nectar plants.

Palicourea fuchsioides (Rubiaceae) and Macleania rupestris (Ericaceae) are the two most frequently visited and important food plants, accounting for nearly 90% of observed feeding visits in some studies. Both are shrubs or small trees with tubular flowers that match the bill length of the Black-breasted Puffleg, facilitating efficient nectar extraction. Palicourea fuchsioides is itself an endemic and threatened species, highlighting the intertwined conservation needs of plant and pollinator.

Other recorded nectar sources include Thibaudia floribunda, Disterigma alaternoides, Racinaea tetrantha (Bromeliaceae), Guzmania sp., and various fuchsias and ericaceous trees. The species has been documented feeding at up to 29 different plant species from 11 families, indicating a degree of dietary flexibility, but the apparent specialization on a few key plants suggests vulnerability to changes in floral resource availability.

Feeding activity is closely tied to the phenology of flowering plants, with peaks in abundance and detectability corresponding to periods of high flower availability, typically in May–June and November–February. The Black-breasted Puffleg forages at various heights, from the understory to the canopy, and is often observed visiting dense patches of flowering shrubs in elfin forest or along forest borders.

Breeding Biology and Nesting Behavior

Breeding in the Black-breasted Puffleg occurs primarily between November and April, coinciding with the rainy season and peak flowering at higher elevations. Males establish and defend small territories, performing courtship displays that involve vertical flights and aerial chases. Courtship may include both sexes joining bodies in flight 25–30 meters above the ground.

The nest is a small, cup-shaped structure built by the female, typically placed above ground in a well-protected location such as a shrub or small tree. The nest is constructed from moss, spider webs, and fine plant fibers, camouflaged with green moss on the outside and lined with soft materials on the inside. The clutch consists of two white eggs, which the female incubates alone.

After hatching, the female feeds the chicks with regurgitated food, primarily insects and nectar. Fledglings are fed for about two weeks after leaving the nest, with the female making frequent feeding visits (every 5 minutes in the first days). Juveniles remain near the nest, making exploratory flights before becoming independent.

Ecological Interactions and Competition

The Black-breasted Puffleg occupies a specialized ecological niche within the high-Andean hummingbird community. It is generally solitary and territorial, with males defending feeding and breeding territories against conspecifics and, occasionally, other hummingbirds.

A notable ecological interaction is the potential competition with the Gorgeted Sunangel (Heliangelus strophianus), a slightly larger and aggressive hummingbird that has expanded its altitudinal range in recent decades. Both species have similar bill morphology and overlap in resource use, particularly at higher elevations. Field studies have documented aggressive interactions and spatial segregation between the two species, with the Black-breasted Puffleg tending to avoid areas with high densities of Gorgeted Sunangels.

The Black-breasted Puffleg is also an important pollinator for certain endemic and threatened plants, such as Palicourea fuchsioides. Its apparent specialization on a few key nectar plants suggests a mutualistic relationship, with potential implications for the conservation of both plant and bird.

Sensitivity to Habitat Disturbance

The species is highly sensitive to habitat disturbance, particularly the loss and fragmentation of mature forest and the creation of abrupt forest edges. Studies have shown that the Black-breasted Puffleg is more likely to be found in plots further from the forest edge, and it is rarely observed in highly disturbed or secondary habitats. This sensitivity is likely due to a combination of physiological stress, reduced resource availability, and increased predation or competition at habitat boundaries.

Habitat restoration and the maintenance of forest tract connectivity are therefore critical for the species’ survival, enabling seasonal movements and access to a diversity of floral resources across the altitudinal gradient.

Climate Change Risks and Future Outlook

Climate Change Impacts

The Black-breasted Puffleg is highly vulnerable to climate change, given its restricted range, specialized habitat requirements, and dependence on high-elevation forests. Projected increases in temperature are expected to shift suitable habitat upslope, potentially pushing the species above the current treeline and reducing the area of available habitat. This “escalator to extinction” effect is a major concern for montane endemics worldwide.

Climate change may also alter the phenology and composition of flowering plants, disrupting the timing and availability of key nectar resources. Increased frequency and severity of fires, changes in precipitation patterns, and the expansion of competitors such as the Gorgeted Sunangel may further exacerbate the species’ decline.

Conservation Recommendations

To secure the future of the Black-breasted Puffleg, integrated conservation strategies are needed, including:

Protection and restoration of high-elevation forest habitats, with a focus on maintaining and reconnecting forest tracts across the altitudinal range.
Propagation and planting of key nectar plants, such as Palicourea fuchsioides and Macleania rupestris, to enhance food availability and support breeding populations.
Community engagement and sustainable land use, reducing pressures from charcoal production, agriculture, and fires.
Long-term monitoring and research, including standardized surveys, camera trap studies, and investigations into plant-pollinator networks and climate change impacts.
Policy advocacy and enforcement, strengthening legal protection for critical habitats and opposing destructive activities such as mining and unregulated development.

Given the species’ extreme rarity and specialized requirements, ex situ conservation (e.g., captive breeding) is not currently considered feasible or necessary, but may become an option if wild populations continue to decline.

Conclusion

The Black-breasted Puffleg is a flagship species for Andean cloud forest conservation, embodying both the extraordinary biodiversity and the acute vulnerability of Ecuador’s montane ecosystems. Its survival depends on the preservation and restoration of high-elevation forests, the maintenance of ecological interactions with key nectar plants, and the mitigation of threats from habitat loss, climate change, and competition.

Despite its critical status, the Black-breasted Puffleg offers a powerful symbol of hope and resilience. Ongoing conservation efforts, scientific research, and community engagement have already achieved important successes, such as the protection of Yanacocha Reserve and the rediscovery of the species in the Cordillera de Toisán. With sustained commitment and innovative approaches, it is possible to secure a future for this remarkable hummingbird and the unique habitats it represents.