The Costa's Hummingbird breeds in the low desert and chapparal regions of California and the desert southwest. The nest is a delicately woven cup, with leaves or lichens fastened to the outside, built low on a protected branch of a bush or small tree. The Costa's Hummingbird winters in northwest Sonora, southeast California, southwest Arizona and Baja California. In southern and central California, Costa's feeds extensively on the red penstemon. Since this plant is found mainly in habitats where Costa's is the only resident hummingbird, it is probably the plant's chief pollinator.