Costa's Hummingbird breeds in dry shrublands of the southwestern United States and nearby Mexico. Adult males show violet on the head and throat, while females are more subdued green-gray.
Adult males have brilliant violet on the crown and throat, with elongated throat feathers extending along the sides of the face. Females are green-gray with paler underparts.
It feeds on nectar and insects, hovering at flowers. Some birds that breed in the western deserts move to coastal California and Baja California for winter.
An extinction-risk assessment has not been added yet.