Western Emerald

Chlorostilbon melanorhynchus

Dagua (Cali) Valle Del Cauca Colombia

Quick Facts

  • Scientific Name: Chlorostilbon melanorhynchus
  • Spanish Name: Esmeralda occidental
  • Family: Trochilidae
  • Known Nicknames: Western Emerald Hummingbird
  • Average Length: 7.5–8 cm / 3.0–3.1 in
  • Average Weight: 2.6–3.5 g / 0.09–0.12 oz
  • Wingspan: 10.0–11.0 cm / 3.9–4.3 in
  • Key Feature: Brilliant iridescent emerald-green plumage and a straight, entirely black bill
  • Primary Diet: Primarily Nectarivore (Nectar and small arthropods)
  • Range: Western slopes of the Andes in Colombia and Ecuador
  • Habitat: Subtropical or tropical moist montane forests, forest edges, and gardens
  • Social Structure: Solitary and highly territorial
  • Nesting/Breeding: Small cup-shaped nests constructed from plant fibers and spiderwebs
  • Conservation Status: Least Concern (LC)
  • Population Trend: Stable

The Western Emerald (*Chlorostilbon melanorhynchus*) is a breathtaking hummingbird native to the lush forest edges and gardens of the Western Andes in Colombia and Ecuador. This small but vibrant bird is defined by the male's brilliant, iridescent emerald-green plumage and a strikingly long, deeply forked, blue-black tail that shimmers during flight. Its most distinctive anatomical feature is its straight, entirely black bill, a trait reflected in its scientific name that sets it apart from many of its close relatives. While the males are a uniform flash of jewel-toned green, the females possess an understated elegance with a pale grey underside and a prominent white stripe behind the eye. Exceptionally agile, these birds are master aerialists, darting between nectar-rich flowers with rapid-fire wingbeats that make them a mesmerizing highlight of the high-altitude Andean landscape.

Fun Facts

These tiny powerhouses are aggressive defenders of their territory, frequently chasing away much larger birds from their favorite nectar sources. They are expert "trap-liners," memorizing specific routes between flowering plants to maximize feeding efficiency throughout the day. To survive the chilly Andean nights, they enter a state of torpor, drastically lowering their body temperature and heart rate to conserve energy. During courtship, males perform dramatic U-shaped aerial dives, using their iridescent feathers to flash like living jewels in the sunlight. Their scientific name, *melanorhynchus*, literally translates to "black beak," highlighting their distinctively dark, needle-like bills used for precision feeding.

Habitats & Distribution

This hummingbird is primarily restricted to the western slopes of the Andes, ranging from south-central Colombia through western Ecuador. It is typically found at elevations between 600 and 2,700 meters, though it may occasionally be seen in lower foothills or higher montane zones depending on seasonal resource availability. Its preferred habitats include humid and semi-humid forest edges, secondary growth, and open woodlands. It is also highly adaptable to human-altered environments, frequently appearing in gardens, agricultural plantations, and scrubby clearings where it can easily access nectar-rich flowering plants.

Behaviours & Reproduction

Typically solitary and highly territorial, these birds aggressively defend nectar-rich floral patches against both conspecifics and other nectarivores. During the breeding season, males engage in a polygynous mating system, performing spectacular aerial displays, including steep U-shaped dives, to attract multiple females. Once mating is complete, the social bond dissolves, as males do not participate in nesting or chick-rearing, focusing instead on maintaining their individual territories. The female is solely responsible for reproductive labor, constructing a small, cup-shaped nest from plant down, moss, and lichen. These materials are bound together with spider silk, providing a flexible structure that expands as the typically two nestlings grow. She incubates the eggs and feeds the young a mixture of nectar and small insects, strategically placing the nest in low, sheltered vegetation to protect the brood from predators and environmental stressors.

Diet

The Western Emerald primarily sustains itself on a diet of high-energy nectar gathered from a diverse array of flowering plants, including species within the Ericaceae, Gesneriaceae, and Bromeliaceae families. Using its specialized long bill and extensible tubular tongue, it extracts sugar-rich liquid to fuel its exceptionally high metabolism, often visiting flowers in a systematic "trap-lining" fashion or aggressively defending productive floral patches from other hummingbirds. To supplement this carbohydrate-heavy intake with essential proteins and minerals, this bird also actively hunts small insects and spiders, which it captures mid-air through agile aerial maneuvers known as hawking or gleans directly from the surface of leaves. An interesting aspect of its feeding ecology is its role as a vital pollinator; while it feeds, pollen adheres to its feathers and bill, facilitating the reproduction of many Andean plant species that have evolved specifically to be serviced by such hovering nectarivores.

Colors

The Western Emerald displays vibrant, iridescent grass-green plumage across its body, with males often featuring a subtle bluish sheen on the throat and a dark, slightly forked bluish-black tail. Females exhibit more muted green upperparts contrasted by grayish-white underparts and a characteristic pale stripe behind the eye. Their shimmering metallic feathers provide effective camouflage by mimicking the dappled light and shifting shadows of their tropical forest habitats.