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: 7.5–8.5 cm / 3.0–3.3 in
  • Average Weight: 2.5–3.5 g / 0.09–0.12 oz
  • Wingspan: 10–12 cm / 3.9–4.7 in
  • Key Feature: Shimmering emerald-green plumage and a short, straight black bill
  • Primary Diet: Nectarivore (Nectar supplemented with small insects)
  • Range: Western Andes of Colombia and Ecuador
  • Habitat: Humid forest edges, clearings, and suburban gardens
  • Social Structure: Solitary and highly territorial
  • Nesting/Breeding: Small cup-shaped nests made of plant fibers and spiderwebs on low branches
  • Conservation Status: Least Concern (LC)
  • Population Trend: Stable

The Western Emerald (*Chlorostilbon melanorhynchus*) is a small, vibrant hummingbird native to the humid Andean slopes of Colombia and Ecuador, where it flits through the air like a living gemstone. The male is particularly striking, draped in shimmering, iridescent emerald-green plumage that contrasts sharply with its deeply forked, blue-black tail. As its scientific name suggests—*melanorhynchus* meaning "black beak"—one of its most defining characteristics is its entirely straight, coal-black bill, which distinguishes it from several similar species that possess reddish lower mandibles. While males are radiant, females display a more subtle beauty with pale grey underparts and a distinctive white streak behind the eye. These energetic birds are known for their territorial nature and remarkable agility, hovering with high-frequency wingbeats as they forage for nectar in high-altitude gardens and cloud forest edges.

Fun Facts

Known for its fiery temperament, the Western Emerald fiercely defends its nectar patches, often diving at birds twice its size to protect its territory. It operates like a tiny commuter, utilizing a "trap-lining" strategy where it follows the exact same floral route every single day to ensure a steady energy supply. To survive freezing high-altitude nights, this hummingbird enters a deep state of torpor, essentially "powering down" its metabolism and lowering its body temperature significantly to conserve energy. Its scientific name, *melanorhynchus*, literally translates to "black beak," a defining trait that contrasts sharply with its shimmering, metallic green plumage.

Habitats & Distribution

This hummingbird is primarily distributed along the western slopes of the Andes Mountains, extending from southwestern Colombia through western Ecuador. It is also found within several inter-Andean valleys. Its range is relatively restricted to the subtropical and lower temperate zones of the northern Andean region, where it remains a fairly common resident. It inhabits a variety of environments, including humid montane forests, cloud forests, and semi-open scrublands. The species is frequently observed in man-made or disturbed habitats such as coffee plantations, suburban gardens, and forest edges where flowering plants are abundant. It typically occurs at elevations between 600 and 2,700 meters, favoring areas where it can easily access nectar sources in the understory and mid-story canopy.

Behaviours & Reproduction

This hummingbird is primarily solitary and exhibits highly territorial behavior, aggressively defending nectar-rich flowering patches from both conspecifics and other species. Its social structure is defined by competitive exclusion, where individuals establish feeding territories through vocalizations and rapid aerial displays. Outside of the brief interactions during courtship, individuals live independently, focusing their energy on maintaining access to high-quality floral resources throughout the Andean slopes. The mating system is polygynous, with males performing elaborate courtship rituals involving steep dives and rhythmic shuttle flights to attract multiple partners. Males provide no parental care; instead, the female takes full responsibility for nest construction, incubation, and chick rearing. She builds a small, elastic cup-shaped nest out of plant down and spider webs, typically laying two eggs. This reproductive strategy relies on the female’s ability to conceal the nest and provide sufficient nourishment for the young without assistance from the male.

Diet

The Western Emerald primarily sustains itself on a diet of nectar sourced from a variety of flowering plants, particularly favoring species within the Bromeliaceae and Fabaceae families. To access these energy-rich sugars, it utilizes a specialized, bifurcated tongue that can rapidly lap up liquid from tubular blossoms, a necessity for fueling its exceptionally high metabolic rate. Beyond its nectar consumption, this hummingbird is an active insectivore, hunting small arthropods and spiders through aerial hawking or by gleaning them from foliage to obtain essential proteins and minerals. An intriguing aspect of its foraging strategy is the practice of trap-lining, where the bird follows a consistent, repeatable route between specific flower patches to ensure a steady food supply. To maintain its energy levels, the Western Emerald must feed frequently throughout the day, often consuming a volume of nectar that rivals its own body weight.

Colors

The Western Emerald is characterized by brilliant metallic green plumage with a golden or bronzy sheen and a notched, bluish-black tail. Males are almost entirely iridescent green with a distinctive all-black bill, while females feature pale grey underparts and a prominent white streak behind the eye. This vibrant green coloration serves as effective camouflage, allowing the bird to blend seamlessly into the lush, sun-dappled foliage of its Andean forest habitat.