Tumbes Hummingbird is a small hummingbird of arid scrub, dry forest edges, and sometimes deciduous forests in northwestern Peru and adjacent southwestern Ecuador. This a very colored hummingbird: both sexes are dull green above and grayish below, with no iridescence at all in the plumage. Tumbes Hummingbird is similar to Spot-throated Hummingbirds (Leucippus taczanowskii), which also occurs in northwestern Peru, but the species rarely occur together: Tumbes Hummingbirds is restricted to lower elevations, but, in the region of geographic overlap, Spot-throated Hummingbird occurs at higher elevations. Spot-throated Hummingbird also is larger and its throat is densely marked with small green speckles. Tumbes Hummingbird feeds on nectar from dry-tolerant plants like cacti and forage for small insects, and its song consists of an assortment of bubbly electric notes. Otherwise almost nothing is known about the biology of this species.