The Violet-headed Hummingbird was described by Mm. Bourcier and Mulsant in 1843. The species name is after M. Guimet who was a chemist from Lyons, France. It is in the hummingbird family (Trochilidae).
The Violet-headed Hummingbird (Klais guimeti) ranges from Central America well into South America. This includes Honduras, Nicaragua, Costa Rica and Panama in Central America and western Venezuela, Colombia, Ecuador, Peru, western Brazil, western Venezuela and northern Bolivia.. The species tends to be local in distribution, common in some areas and rare in other seemingly identical areas. 
The Violet-Headed Hummingbird occurs in the mountains and has been recorded to occur from 200 to 850 meters in Costa Rica , from 400 to 1850 meters in Colombia and 150 to 1900 meters in Venezuela 
Violet-headed Hummingbird are found on the edges of humid primary forest, openings in secondary forests, in shrub and thicket clearings  and in various human modified habitat such as Stachytarpheta hedges in Costa Rica  and shaded coffee plantations in Venezuela .
In Costa Rica males sing in loose leeks  beginning in October and intensifying until the breeding season in December. The chorus continues until the dry season causes the flowers to disappear in the February to March time frame. The chorus picks up again when the rains begin again in April, but the heavy rains of May shut the chorus down again until October. The leeks are located 5 to 18 meters above the ground on the edge of clearings where the males sing conspicuously from slender dead twigs. Occasionally, an individual will sing solo without other Violet-Headed Hummingbirds near by.
The nest is a mossy cup  built 1 to 5 meters above forested mountain streams . They are normally built in February , but sometimes as early as January. The last young fledge in May.
The Violet-headed Hummingbird drinks nectar from understory flowering shrubs as well as taking small insects on the wing. In Costa Rica, a particular fondness for Stachytarpheta flowers has been reported with as many as one individual every 5-7 meters on a hedge near Murcia .
The Violet-headed Hummingbird has been designated as a species of least concern due to its large range and ability to exist in human modified habitat. The flowering shrubs near Murcia were reported to be in an area cleared for agriculture with very few trees.
 Hilty, p.262
 Dunning, p.225
 Skutch, p. 5
 Schauensee , p. 139
 Hilty, p. 249
Skutch, p. 7
 Jones, p. 408
 Skutch, p.6
Skutch, p. 9
 Skutch, p. 9 & 10
 Skutch, p. 11
Dunning, John S & Ridgely, Robert S. 1982. South American Land Birds. Harrowood Books.
Hilty, Steven L., & Brown, William L. 1986. Guide to the Birds of Colombia. Princeton University Press
Jones, Jason & Ramoni-Perazzi, Paolo & Carruthers, Erin H. & Robertson, Raleigh. 2002. Species Composition of Bird Communities in Shad Coffee Plantations in the Venezuelan Andes. Ornithologia Neotropical 13: 397-412, 2002
Schauensee, Rodolphe Meyer & Phelps, William H. 1978. A Guide to the Birds of Venezuela. Princeton University Press
Skutch, A. F. 1958. Life history of the Violet-headed Hummingbird. Wilson Bull. 70:5-19.