Blue-tailed Emerald

Characterized as a small-sized apodiform bird, this micro-vertebrate typically measures between 7.5 and 9 centimeters in length and has a body mass of approximately 2.6 to 3.5 grams. The male exhibits a dazzling, iridescent bright green plumage over most of its body, with a more golden hue on its back and an intensely glittering chest. Its tail is deeply notched and colored in dark metallic blue, appearing almost black in certain light conditions. The bill is straight, short, and black, measuring between 13 and 18 millimeters. In contrast, the female displays a pronounced sexual dimorphism, featuring bronzy-green upperparts and pale greyish to whitish underparts. Additionally, she presents a dark facial mask highlighted by a conspicuous white postocular stripe and white-tipped outer tail feathers. Immature individuals resemble the adult female but exhibit buffy fringes on the feathers of their nape and rump.

Geographical distribution: This species is widely distributed across the neotropical regions of northern South America. Its range spans continuously and patchily through Colombia, Venezuela, Ecuador, Peru, the Guianas (Suriname, Guyana, and French Guiana), as well as northern Brazil and the islands of Trinidad and Tobago. Along the Andean slopes, its altitudinal distribution extends from sea level up to approximately 1800 meters above sea level, though it is considerably more abundant in warm inter-Andean valleys and lowlands.

Habitat: It primarily frequents semi-open ecosystems and secondary growth areas. It is regularly found in wooded savannas, dry deciduous forests, arid scrublands, forest edges, agricultural fields, coffee plantations, urban parks, and domestic gardens. It displays high tolerance to habitats modified by human activities, colonizing disturbed areas as long as there is a continuous supply of floral resources and suitable perches for resting and territorial surveillance.

Feeding: Its diet consists mainly of nectar extracted from a wide variety of flowering plants, particularly those belonging to the Fabaceae, Rubiaceae, Acanthaceae, Malvaceae, and Verbenaceae families. Its primary feeding technique involves hovering flight, inserting its short bill into small to medium-sized corollas. It complements this carbohydrate-rich diet by capturing small arthropods, including dipterans, small beetles, and spiders, which are caught on the wing through aerial hawking or gleaned directly from leaves and spider webs.

Behavior: It exhibits highly territorial and aggressive behavior, vigorously defending its feeding territories from other hummingbirds and large insects such as sphinx moths (Sphingidae). It is an extremely agile and rapid flyer, executing direct flights with wing beats too fast for the human eye to perceive. Although considered a resident species throughout most of its range, it may undergo local altitudinal movements and short-distance seasonal migrations linked closely to the flowering cycles of local flora.

Nesting: The reproductive process is carried out entirely by the female, who takes full responsibility for nest construction, incubation, and rearing. She constructs a delicate, tiny cup-shaped nest using fine plant fibers, seed down, and mosses, binding the structure together with spider silk to provide elasticity. The nest is typically secured onto low, thin horizontal branches of shrubs or small trees, usually between 1 and 2 meters above the ground. The clutch size consists of two white eggs, which are incubated for 13 to 16 days. Upon hatching, the altricial chicks remain in the nest for 18 to 22 days and are fed regurgitated nectar and soft-bodied insects by the female.

Conservation status: It is currently classified as Least Concern (LC) on the IUCN Red List of Threatened Species. Its extensive geographical distribution, combined with its high capacity to adapt to human-modified landscapes and a population trend that is believed to be stable, ensures that the species faces no imminent threats of extinction, despite localized habitat degradation driven by urban and agricultural expansion.