The white-necked jacobin (Florisuga mellivora) is a medium-sized hummingbird that ranges from Mexico south through Central America and northern South America into Brazil, Peru, and Bolivia. It is also found in Trinidad and Tobago. When in 1758, Swedish naturalist Carl Linnaeus updated his Systema Naturae for the 10th edition, he placed the white-necked jacobin with the other hummingbirds in the genus Trochilus. Linnaeus included a brief description, coined the binomial name Trochilus mellivorus, and cited Edwards' work. The specific epithet combines the Latin mel and -vorus, meaning "honey eating". The type locality is Suriname. The white-necked jacobin is now placed in the genus Florisuga that was introduced in 1850 by Charles Bonaparte.</small>
Description
The white-necked jacobin is long. Males weigh and females . The male is unmistakable with its dark blue head and chest and white belly and tail; the tail feathers have black tips. A white band on the nape separates the blue head from the bright green back and long uppertail coverts. Females are highly variable, and may resemble adult or immature males. Most females have green upperparts, a blue-green throat and breast with white "scales", a white belly, and a mostly green tail with a blue end. Immature males vary from female-like, but with more white in the tail, to male-like with more black there. Immature females also vary, but usually have less white in the tail and are somewhat bronzy on the throat and chest.
The white-necked jacobin inhabits the canopy and edges of humid forest and also semiopen landscapes such as tall secondary forest, gallery forest, and coffee and cacao plantations. It is usually seen high in trees, but comes lower at edges and in clearings. In elevation, it usually ranges from sea level to about , but rarely has also been seen as high as .