Like many hummingbirds in the region, it can be found on the Pacific coast, often visiting backyard hummingbird feeders and gardens with flowering plants, as well as in more wild ecosystems, such as the conifer and oak forests, chaparral, and high desert habitats found further inland.

[5] The type locality is Magdalena Bay, on the Pacific west coast, of the Mexican state of Baja California Sur.

[3] Costa's hummingbird is common in the arid brushy deserts and gardens of the Southwestern United States and the Baja California Peninsula of Mexico.

[12] The male makes a high-speed dive pass or hover close to the female, perched on a nearby branch, and is accented by a high-pitched vibration that is produced by tail feathers.

[3] The female constructs a small cup-shaped nest out of plant fibers, down, and at times spider silk, coated with lichen to hold it together.