White-necked Jacobin (Florisuga mellivora)
The white-necked jacobin (Florisuga mellivora) is a large and attractive hummingbird that ranges from Mexico south toPeru, Bolivia and south Brazil. It is also found on Tobago (sub-species F. m. flabellifera) and in Trinidad (sub-species F. m. mellivora)
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 conspicuous 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. source