Esmeralda Coliazul
Blue-tailed Emerald
Chlorostilbon (mellisugus) mellisugus
Song
Blue-tailed Emerald
Appearance: A very small, slender emerald hummingbird with a short, straight black bill. Adult males are predominantly glittering emerald- to golden-green, with conspicuous white thigh tufts and a dark, steel- to deep-blue tail that is distinctly forked; adult females are duller above and pale gray to gray-white below, with a dusky facial/auricular area, a pale post-ocular stripe, and whitish tips to the outer tail feathers. Immature males pass through a female-like stage before becoming almost entirely green, which can complicate field identification.
Habitat: The species is chiefly associated with lowland and lower-foothill semi-open habitats, not with intact closed-canopy forest. Across its range it uses savanna, scrub, gallery woodland, forest edge, cultivation, gardens, and large clearings; in upper Amazonia it is also linked to riverine and floodplain habitats. Colombian evidence fits that pattern closely: historical review emphasizes open, brushy, seasonally dry or edaphic scrub habitats in eastern Colombia, including savanna-linked landscapes, while recent media records from Meta and Casanare come from reserve and farm mosaics embedded in Llanos landscapes. A Colombian atlas model also excluded climatically suitable west-Andean areas because they are not known to be occupied, reinforcing the essentially east-Andean lowland character of the species in the country.
Behavior: The available evidence indicates a typical small-emerald strategy centered on floral nectar plus small arthropods. The species forages actively in openings and edges, and broader hummingbird foraging work by Stiles includes C. mellisugus among the straight-billed species that commonly hawk arthropods from a perch. Species summaries also describe it as a trap-liner at flowers that may locally defend rich nectar patches, but detailed Colombian studies of territoriality, seasonal movement, or daily activity budgets are still lacking; in practical field terms, it should be expected in sunny, flower-rich microhabitats and ecotones rather than in shaded forest interior.
Breeding: Breeding is one of the least well-documented aspects of the species in Colombia. Published nests from elsewhere in the range show a very small cup constructed of soft vegetable down bound with spider silk and externally decorated with bark or lichen, usually set on a sloping branch in dense secondary vegetation; clutch size is two white eggs, incubation lasts about 13–19 days, and fledging occurs roughly 18–20 days after hatching. Regionally, the Caribbean population has been reported as capable of breeding through much of the year, a Venezuelan nest with fresh eggs was found in late December, and an incomplete nest was reported in June in south-west Amazonian Brazil. Those scattered records strongly suggest flexible timing linked to local flowering and rainfall, but they do not yet define a reliable Colombian breeding calendar.
Conservation Status: Blue-tailed Emerald is currently treated as a species of relatively low global conservation concern.
MALE
FEMALE
MALE
MALE
Distribution
The Blue-tailed Emerald (Chlorostilbon (mellisugus) mellisugus) should be mapped primarily east of the Andes. Found in Meta and Casanare in the Llanos, documented by recent Macaulay/eBird media, plus a Vaupés sound record indexed in a regional sound compilation. Beyond those documented departments, the broader eastern Colombian lowlands almost certainly hold the species more widely, but the confidence level varies by department because published Colombian sources are taxonomically heterogeneous. Older Colombian literature assigned eastern populations to caribaeus in Arauca and Meta and to napensis in the south-east, whereas a Colombian atlas based on specimen and occurrence modeling inferred an intergradation zone between caribaeus and phoeopygus around Serranía de La Macarena and excluded all west-Andean climatically suitable areas as unoccupied. Modern country lists, meanwhile, separate Blue-tailed Emerald from Western Emerald, Red-billed Emerald, and Chiribiquete Emerald, so many older west-Andean Colombian records once labeled C. mellisugus are not referable to the current species concept. The safest analytical reading is therefore: documented in Meta, Casanare, and Vaupés; likely broader across the east-Andean lowlands; subspecies limits uncertain and still needing revision in Colombia.
Taxonomy
The Blue-tailed Emerald (Chlorostilbon (mellisugus) mellisugus)
- Kingdom: Animalia
- Phylum: Chordata
- Class: Aves (Birds)
- Order: Caprimulgiformes
- Family: Trochilidae
- Genus: Chlorostilbon
- Species: mellisugus
- Subspecies: mellisugus
Vocalization
Contact Call: The contact call is a very short, high, thin note, often sounding like “tsip,” “tsee,” or “tseet.” It is usually given while the bird is moving through open vegetation, gallery woodland, gardens, savanna edges, or forest-edge habitats. Because this species is tiny and fast, the call can sound almost insect-like.
Feeding Call: The feeding call is a light, sharp, high-pitched chip, often written as “tsit,” “tsip,” or “tseep.” Xeno-canto includes a recording specifically labeled as call / feeding calls for the Blue-tailed Emerald, showing that these notes are given while the bird is feeding or moving among flowers.
Territorial Call: Around flowers, the Blue-tailed Emerald may give sharper repeated notes when another hummingbird approaches. These calls are probably similar to the feeding call but more forceful and repeated more quickly, like “tsip-tsip-tsip!” They are used during short disputes over nectar sources.
Aggressive Call: During chases, the call may become a rapid series of high squeaky chips, such as “tsee-tsee-tsee” or “tsip-tsip-tsip.” These notes are brief, dry, and excited, and may be heard when one bird drives another away from a flowering shrub or perch.
Advertisement Call: The Blue-tailed Emerald does not have a rich, complex song like a songbird. Its “song-like” sounds are probably repeated high notes or short phrases given from a perch.
