Costa's Hummingbirds occur in Sonoran and Mojave Desert scrub, coastal California chaparral and sage scrub, and deciduous forest and desert scrub in Baja California, Mexico. In the Sonoran Desert they occur in desert washes with palo verde, jojoba, desert lavender, or chuparosa, on steep rock slopes, and in lowlands with saguaro, creosote bush, and cholla cacti typically below 3,000 feet elevation. In the Mojave Desert they frequent scrub and woodlands near springs and streams with cottonwoods, brittlebrush, four-winged saltbush, and other species from near sea level to 4,000 feet elevation. Along the California coast they use sage scrub and chaparral. Along the Baja peninsula they use desert scrub and deciduous forests with cardon cacti, elephant tree, Adam's tree, and tree morning-glory. Back to top
Costa's Hummingbirds feed on nectar and small flying insects. In the Sonoran Desert, they visit at least 22 different plant species, but feed most frequently on chuparosa and ocotillo. In California coastal scrub they frequently feed at white and black sage, tree tobacco, heart-leaved penstemon, and bush monkeyflower, among others. Back to top
Female Costa's Hummingbirds typically build a nest 3–7 feet above the ground in palo verde, ironwood, cholla, acacia, graythorn, and other shrubs. She frequently places the nest in relatively open areas without much vegetation cover.
Females collect strips of bark, small leaves, bits of lichen, and downy parts from flowers in the sunflower family. She loosely weaves all of these materials together with spiderweb to form a rather flimsy cup-shaped nest. It takes her about 4–5 days to complete a nest. The outside of the nest measures around 1.25 inches and is about 1 inch deep. Females occasionally build a new nest on top of one from a previous season.
|Number of Broods:||1-2 broods|
|Egg Length:||0.4-0.6 in (1.1-1.4 cm)|
|Egg Width:||0.3-0.3 in (0.8-0.9 cm)|
|Incubation Period:||15-18 days|
|Nestling Period:||20-30 days|
|Condition at Hatching:||Naked and helpless with dark skin.|
Costa's Hummingbirds hover above flowers to take nectar and catch small flying insects in midair. Males defend territories during the breeding season around prominent perches and nectar sources. They pick 3–4 favorite perches within their territory, usually a dead twig in a palo verde, acacia, or ironwood, and sing a thin high-pitched whistle to proclaim ownership and keep intruders out. Males perform a looping dive display to entice females to mate with them and also to threaten intruding hummingbirds. They fly straight towards the female, make several loops around her and then fly straight up into the air, returning in a broad U-shaped dive. During the dive they sing a high-pitched whistle. They continue to loop around and perform dives for the female without pause, sometimes for up to 4 minutes, but usually the display lasts for about 35 seconds. If that was not enough to attract the female’s attention, they also hover directly in front of her with their gorget flared. Males typically mate with more than one female and do not help care for the young. Birds breeding in the Sonoran Desert leave the area in the summer and fall, heading towards the coast and areas with abundant flowers. Males and females defend patches of flowers during the nonbreeding season, but they often move around to take advantage of blooming plants. Although they defend nectar sources they are not as aggressive and are subordinate to larger hummingbirds. Back to top
Costa's Hummingbirds are relatively common, and their populations were fairly stable or slightly declining between 1968 and 2019, according to the North American Breeding Bird Survey. Partners in Flight estimates that the global breeding population is 3.4 million and rates them 11 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. Clearing of desert scrub for development and grazing is their biggest threat.Back to top
Baltosser, William H. and Peter E. Scott. (1996). Costa's Hummingbird (Calypte costae), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
Dunne, P. (2006). Pete Dunne's essential field guide companion. Houghton Mifflin Harcourt, New York, USA.
Lutmerding, J. A. and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory 2020.
Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.
Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2019). The North American Breeding Bird Survey, Results and Analysis 1966–2019. Version 2.07.2019. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.
Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.