Fork-tailed Woodnymph

Belongs to the family Trochilidae and is characterized as a medium-sized hummingbird that exhibits striking sexual dimorphism. Adult males measure between 9.5 and 11 centimeters in length and weigh approximately 4.1 to 4.5 grams. They feature highly iridescent plumage, highlighted by a glittering emerald-green throat and breast, a distinct violet-purple band across the upper back and abdomen, and a deeply forked blue-black tail. In contrast, females are smaller, measuring 8 to 9 centimeters and weighing about 3 to 3.5 grams. Their coloration is significantly duller, showing a bright green upper body, uniformly pale gray to whitish underparts, and a less forked tail with outer feathers tipped in conspicuous white. Both sexes possess a black, slightly decurved bill measuring around 20 to 22 millimeters.

Geographical distribution: It is widely distributed across a vast range of South America, east of the Andes. Its geographical range encompasses almost the entire Amazon Basin and the Guiana Shield. It is found in countries including Colombia, Venezuela, Guyana, Suriname, French Guiana, Ecuador, Peru, Bolivia, Brazil, Paraguay, and northeastern Argentina, specifically within the Misiones Province. Due to this immense geographic extension, several subspecies of Thalurania furcata are recognized, showing minor variations in the size, hue, and distribution of the green and violet tones in their plumage.

Habitat: This hummingbird primarily inhabits the understory and mid-story of lowland humid forests, including terra firme and seasonally flooded forests known as várzea. It is also frequently found in mature secondary forests, forest edges, shaded coffee and cacao plantations, semi-open clearings, and suburban gardens rich in flowering vegetation. Although it is predominantly a lowland species, it can ascend the foothills of the Andes and other highland formations, reaching elevations up to 1200 meters above sea level.

Feeding: Its diet is primarily nectarivorous, heavily supplemented by small arthropods. It feeds on the nectar of a diverse array of flowering plants, showing a strong preference for families such as Bromeliaceae, Rubiaceae, Fabaceae, Heliconiaceae, and Myrtaceae. To satisfy its protein requirements, it captures small insects in mid-air using agile aerial maneuvers known as hawking, and gleans spiders directly from the undersides of leaves. Its highly extensible, bifurcated tongue is perfectly adapted to extract liquid food from deep flower corollas.

Behavior: It exhibits highly territorial and aggressive behavior when defending high-quality nectar sources. Males vigorously defend rich floral patches against other hummingbirds and large insect competitors. However, in areas where floral resources are sparse, it employs a "traplining" foraging strategy, moving systematically along a fixed circuit of scattered plants. Its flight is exceptionally agile, rapid, and precise, allowing it to hover motionless in front of flowers while feeding. It is a solitary species, interacting closely with conspecifics only during courtship displays.

Nesting: The reproductive cycle is managed entirely by the female, who takes on all nesting and parental care duties. She constructs a tiny, deep cup-shaped nest typically placed in a horizontal fork of a low branch in the understory, situated between 1 and 5 meters above the ground. The nest is built using soft plant fibers, seed down, and mosses, held together and secured to the branch with sticky spider silk, which allows the nest to stretch as the chicks grow. The outer walls are meticulously camouflaged with bits of lichen. The typical clutch consists of two white eggs. Incubation lasts 15 to 17 days, and the female feeds the chicks by regurgitation until they fledge at approximately 20 to 22 days of age.

Conservation status: It is currently classified as Least Concern (LC) on the IUCN Red List of Threatened Species. Although it possesses an extremely large global population and an extensive geographical range, it faces ongoing threats from habitat loss and fragmentation caused by deforestation and agricultural expansion in the Amazon. Nonetheless, its ability to tolerate moderate levels of forest disturbance and utilize secondary habitats allows it to maintain stable populations across most of its distribution.