A mature rufous hummingbird is about 7-9 cm in length, has an 11 cm wingspan, and weighs between 2 and 5 g. Males have an iridescent red throat, a dull reddish back, and an orange tail with pointed black tips. Females have a white throat with a few red feathers, a green back and head, and an orange, green, and black tail. Rufous hummingbirds feed on flower nectar, small insects, and tree sap. Males can be identified by their aerial display during courtship in which they make a series of steep, J-shaped dives that end at the same point. Males are territorial year-round.

This bird can be found in the winter from Southern California, through Mexico, and along the northern Gulf Coast. In the summer, it breeds from southern Alaska southward to northern California, south central Idaho, and western Montana. These birds frequently visit the eastern states and have the northernmost range of any hummingbird. Selasphorus rufus is declining over most of its range.