The White-necked Jacobin (Florisuga mellivora) is a large and attractive hummingbird that ranges from Mexico south to Peru, Bolivia and south Brazil. It is also found on Tobago and in Trinidad, but breeding has not been proved on the latter island.

Other common names are Great Jacobin and Collared Hummingbird.

The White-necked Jacobin is a widespread inhabitant of forest, usually being seen at a high perch or just above the canopy. It is less common at lower levels, except near hummingbird feeders.

The approximately 12 cm long male White-necked Jacobin is unmistakable with its white belly and tail, a white band on the nape and a dark blue hood. Immature males have less white in the tail and a conspicious rufous patch in the malar region. Females are highly variable, and may resemble adult or immature males, have green upperparts, white belly, white-scaled green or blue throat, and white-scaled dark blue crissum, or be intermediate between the aforementioned plumages, though retain the white-scaled dark blue crissum. Females are potentially confusing, but the pattern on the crissum is distinctive and not shared by superficially similar species.

These birds usually visit flowers of tall trees and epiphytes for nectar, and also hawk for insects.