Red-tailed Comet is among the most gorgeous of all hummingbirds. The male is largely green, with a glittering gorget, and buffy belly, but the striking coloration of this hummingbird is all on the back. It is a long-tailed hummingbird with the tail slightly longer than the length of the body. Above, the green head contrasts with a reddish violet back and rump, while the tail shows a fantastic greenish bronze color which at the right angle looks strawberry red; each tail feather also has a broad and square-ended black tip. Red-tailed Comet is found in the Andes from central Bolivia south into northern Argentina, as well as on isolated mountains of Córdoba. It is fond of arid shrubby slopes, often where there are cacti, ranging to 2000 m elevation in the south, and higher in the north. Red-tailed Comet is primarily resident, but there is some down slope movement in the northern portion of its range in Bolivia.