Rivoli's Hummingbird is a large, long-billed hummingbird that occurs in the highlands from the southwestern United States south to northern Nicaragua. A related species, Talamanca Hummingbird (Eugenes spectabilis), is found in the highlands of Costa Rica and western Panama; these two formerly were classified as a single species, Magnificent Hummingbird (Eugenes fulgens). Rivoli's Hummingbird is found in pine-oak and pine-evergreen forests and forest edges. Most populations are resident, but the species migrates south from the northern part of the range in the nonbreeding season. Both sexes are primarily green above, with a prominent white postocular spot. The male also has a glittering violet forecrown. The sexes have strikingly different patterns on the underparts. The male has a glittering green gorget and a black or blackish breast, whereas the female is uniformly grayish white below. Although this species is large and is fairly common, its natural history is not well known.
Rivoli's Hummingbird is named in honor of Francois Victor Massena, the Duke of Rivoli, who had an interest in ornithology and assembled a large collection of birds specimens; this collection later was acquired by the Academy of Natural Sciences of Philadelphia. Slaty-tailed Trogon (Trogon massena) also was named after the Duke, and Anna's Hummingbird (Calypte anna) was named in honor of his wife, the Duchess of Rivoli.