Rivoli's Hummingbird was named in honor of the Duke of Rivoli when the species was described by René Lesson in 1829 (1). Even when it became known that William Swainson had written an earlier description of this species in 1827, the common name Rivoli's Hummingbird remained until the early 1980s, when it was changed to Magnificent Hummingbird. In 2017, however, the name was restored to Rivoli's Hummingbird when the American Ornithological Society officially recognized Eugenes fulgens as a distinct species from E. spectabilis, the Talamanca Hummingbird, of the highlands of Costa Rica and western Panama (2). See Systematics: Related Species.
Rivoli's Hummingbird is found from the southwestern United States to northern Nicaragua, and is the second-largest hummingbird species in the United States. It exhibits sexual dimorphism, primarily in coloration, body mass, and bill length. The species typically occurs at middle to high elevations throughout much of Mexico and Central America. Birds migrate north in early spring to breed, some of them reaching forested mountains at the northern limit of the breeding range in Arizona and New Mexico. Throughout its range, Rivoli's Hummingbird occurs in a variety of habitats, but it is most frequently found in dry pine–oak (Pinus–Quercus) forests. Breeding is often associated with cool canyons and drainages in the mountain ranges of southern Arizona and New Mexico, where nests are often constructed high up in trees that overhang streams.
Despite the extensive range and abundance of the Rivoli's Hummingbird, its basic life history is largely unknown, with most information coming from studies in central and southern Mexico. The transient nature of males and the secretive habits of females have made research in the U.S. difficult, although it appears that northern males may forage more by traplining (see Behavior: Agonistic Behavior) than by being territorial and aggressive. Additional information is needed on migration and movement ecology, breeding biology (courtship, nest construction, number of broods, nestling development, parental care), breeding success, feeding behavior (dietary importance of insects; role of bill dimorphism in feeding efficiency), and the function of vocalizations.