Oasis Hummingbird is a mid-sized hummingbird with a long, decurved bill. Males are green above, with blue to reddish gorget, a long forked tail and a distinctive cinnamon colored rump. It does well in various vegetated habitats from desert oases and arid scrub to urban areas and gardens in the extremely dry coastal desert in Peru and northern Chile; it is currently expanding its range south in Chile. Curiously, birds in the far north and far south of the range are distinctly smaller than those in the central part of the range. Although it ranges to above 3000 m, Oasis Hummingbird largely is restricted to the coastal slope in the arid coastal zone influenced by the Humboldt Current. Migrations and large scale movements are not known, but Oasis Hummingbird has been known to colonize isolated valleys and oases, so at times it must perform exploratory movements.