About Florisuga mellivora (Linnaeus, 1758)
Florisuga mellivora, the white-necked jacobin, measures 11 to 12 cm (4.3 to 4.7 in) long. Males weigh 7.4 to 9.0 g (0.26 to 0.32 oz), while females weigh 6.0 to 9.2 g (0.21 to 0.32 oz). Males are highly distinctive, with dark blue heads and chests, white bellies and tails, and black-tipped tail feathers. A white band on the nape separates the blue head from the bright green back and long uppertail coverts. Females show high variation in appearance, and may resemble adult or immature males. Most females have green upperparts, a blue-green throat and breast marked with white "scales", a white belly, and a mostly green tail that ends in blue. Immature males vary from female-like plumage (with more white in the tail) to male-like plumage (with more black in the tail). Immature females also vary, but usually have less white in the tail, and have somewhat bronzy coloration on the throat and chest. Two subspecies of white-necked jacobin are recognized. The nominate subspecies, F. m. mellivora, ranges from southern Veracruz and northern Oaxaca, Mexico, south through southern Belize, northern Guatemala, eastern Honduras and Nicaragua, eastern and western Costa Rica, and Panama into South America. Within South America, it occurs across most of Colombia and Ecuador, eastern Peru, northern Bolivia, most of Venezuela, the Guianas, the northwestern half of Brazil, and the island of Trinidad. The second subspecies, F. m. flabellifera, is found only on the island of Tobago. The nominate subspecies has been recorded as a vagrant in Argentina, and on the islands of Aruba and Curaçao. The white-necked jacobin lives in the canopy and edges of humid forest, as well as in semi-open landscapes including tall secondary forest, gallery forest, and coffee and cacao plantations. It is most often seen high in trees, though it moves lower to forest edges and clearings. In terms of elevation, it typically ranges from sea level to around 900 m (3,000 ft), and is rarely found as high as 1,500 m (4,900 ft).
