The already small area inhabited by the endangered Black-backed Thornbill is shrinking drastically due to extensive deforestation, overgrazing, and burning. These hummingbirds are found only in the Santa Marta mountains of Colombia in humid and elfin forests, bush-filled slopes near treeline, and in páramo. They forage at all levels but spend much of their time in the canopy where they gather with other hummingbirds at flowering trees or pause to perch in the treetops. Black-backed Thornbills have very short bills and purplish-black forked tails. Males are mostly black above, while females are bronzy green above and whitish below speckled with green on the throat and sides of the body.