The Broad-tailed Hummingbird is the major breeding hummingbird of higher elevations in the southern and central Rocky Mountains, eastern California, and Mexico. In the mountains of the western United States, its breeding season is characterized by a brief flowering season and often chilling nocturnal climate in which selection of appropriate microclimate and the ability to undergo torpor are necessary responses. Throughout its range, the species is most abundant in open subalpine meadows and shrubby habitats with nearby forests. It feeds on nectar, usually avoiding flowers recently visited, and on small insects, caught on the wing or snatched from vegetation. A promiscuous breeder, courting male Broad-tailed Hummingbirds perform spectacular aerial displays—a series of high climbs, dives, and hovers, accompanied by a loud wing trill that is heard also during aggressive territorial displays.
This hummingbird has been the subject of many detailed studies of its physiology and feeding ecology. Named from a specimen taken in Mexico in 1834 by William Bullock, who sent the specimen to England for William Swainson to describe. The species was first collected in the United States by J. H. Clark in 1851 near El Paso, Texas. Elliot Coues incorrectly attributed its discovery to Meriwether Lewis and William Clark in Idaho, outside of the current breeding range (Banks and Calder 1989).