Costa's Hummingbird: The Desert Species With a Mustache-Shaped Gorget

Most male hummingbirds wear their iridescent throat patch, the gorget, as a neat, contained bib. The male Costa's Hummingbird (Calypte costae) does something stranger: the feathers flare out past the sides of his head entirely. Cornell Lab's All About Birds describes it plainly, bright purple feathers that stick out wildly to each side, like an overgrown mustache. That single detail is the fastest way to separate this small desert specialist from the similar-looking hummingbirds it shares range with, chiefly Anna's Hummingbird. Here's what actually holds up for identifying a Costa's, plus the desert biology, courtship display, and foraging math that make this one of the more specialized hummingbirds in North America.

The Gorget: Purple, Flared, and Hard to Mistake Once You've Seen It

Per Cornell's identification page, the male's throat and crown both carry that same iridescent purple, and the gorget feathers extend well past the width of his head at the sides rather than sitting flat against the throat the way a typical gorget does. Audubon's field guide describes the same feature from a different angle, noting the gorget feathers extend "back to a point" along the neck, giving the whole throat patch a winged, almost whiskered look in good light. Like all hummingbird iridescence, the color is structural rather than pigment-based, produced by microscopic feather structures that reflect light at specific angles, which our separate guide to hummingbird colors covers in full. The practical version: at the wrong angle, the gorget can read as dark or even black, the same way it does in most iridescent species, but the flared, oversized shape of the patch is visible in silhouette even when the color itself isn't catching the light.

Females look nothing like the males and lack a gorget entirely. Cornell describes them as "greenish above with a white eyebrow stripe, a grayish cheek patch, and whitish underparts," a combination that, without the purple throat to anchor an identification, can look like a number of other small desert or coastal hummingbirds at a glance. For the general framework used to sort out any US hummingbird species by gorget color, size, range, and season, see our guide to the hummingbird species you'll actually see; this post applies that framework specifically to the identification problems Costa's Hummingbird creates.

Costa's vs. Anna's: The Comparison That Actually Matters

Anna's Hummingbird is the species Costa's gets confused with most often, since their ranges overlap across much of the Southwest and both males carry an iridescent crown in addition to a colored throat. The distinction comes down to color and shape together. Anna's Hummingbird carries rose-pink to magenta iridescence across a full, connected hood covering both crown and throat, a look our separate Anna's Hummingbird identification guide covers in depth. Costa's runs purple rather than rose-pink, and instead of a smooth, connected hood, the gorget flares outward past the sides of the head in that mustache-like shape Cornell describes. Size offers a secondary clue: Cornell places Costa's as "larger than a Calliope Hummingbird, smaller than an Anna's Hummingbird," so a bird that reads as noticeably smaller and more compact than a known Anna's, with purple rather than rose-pink color, points toward Costa's.

A Genuine Desert Specialist

Costa's Hummingbird is also genuinely small next to most of the hummingbirds people expect to see in the Southwest, which trips up identification on its own. Cornell places it as "larger than a Calliope Hummingbird, smaller than an Anna's Hummingbird," putting it squarely in the middle of the size range for US hummingbird species, and both sexes weigh only about 2 to 3 grams, roughly the mass of a couple of paperclips. Combined with the desert habitat, that small size means Costa's Hummingbird can be easy to miss entirely against pale, sun-bleached vegetation unless a male happens to be catching direct light at the right angle to flash that purple gorget.

Where most North American hummingbirds treat the desert as one habitat among several, Costa's Hummingbird is built for it specifically. Per Cornell's overview page, the species lives in "the Sonoran and Mojave Deserts as well as in the cooler air of coastal scrub," with birds typically present in the desert from February through May before many shift toward the California coast, where sightings peak in May. That seasonal pattern is loosening, though. Per Audubon's field guide, "where flowers are present all year, as in many suburban gardens, increasing numbers of Costa's Hummingbirds now remain all year" rather than following the older desert-to-coast migration pattern, a shift that tracks with how much residential and garden habitat has expanded across the Southwest.

Surviving in true desert habitat requires real physiological tricks, and Costa's Hummingbird uses the same one most desert-adapted hummingbirds rely on: torpor. Cornell notes the species can "enter a torpid state, with slowed heart rates and reduced body temperatures, when nighttime temperatures are low," dropping a heart rate that normally runs 500 to 900 beats per minute down to roughly 50 beats per minute overnight. That's a roughly tenfold drop, conserving enough energy to survive a cold desert night on a body that weighs about as much as a couple of paperclips.

The Math Behind Desert Foraging

Feeding in a habitat this sparse takes real volume. Cornell's overview cites research finding that "a Costa's Hummingbird needs to visit 1,840 flowers to meet its energy requirements for one day," a number that only makes sense once you factor in how small and nectar-poor individual desert blooms tend to be compared to a garden flower bed. Per Cornell's life history page, the species visits at least 22 different plant species in the Sonoran Desert, with particular preference for chuparosa and ocotillo, while coastal populations shift toward white and black sage, tree tobacco, and bush monkeyflower. The diet isn't nectar-only either; like other hummingbirds, Costa's supplements with small flying insects, which supply protein that flower nectar can't.

A Courtship Dive Set to a Whistle

Male Costa's Hummingbirds court females with an aerial display built around sound as much as motion. Per Audubon, "the male Costa's Hummingbird flies high, then zooms down past a perched female and climbs again, making a shrill high-pitched whistle during the dive." Cornell's life history page adds detail on the buildup: the male performs "several loops around her" before executing the dive itself, with the full display sometimes running up to four minutes. Mating in this species is not paired off long-term. Per Cornell, "males typically mate with more than one female and do not help care for the young," a polygynous system common across hummingbirds generally, and one our guide to whether hummingbirds mate for life covers across species.

Nesting in a Landscape With Almost No Tall Trees

Nest-building reflects the desert habitat as much as the foraging does. Per Cornell's life history page, females build low, typically 3 to 7 feet above ground, in desert shrubs like palo verde and cholla rather than the taller deciduous trees other hummingbird species favor. Construction is fast, roughly 4 to 5 days, using a loose weave of "bark, small leaves, bits of lichen" bound together with spiderweb, producing a finished nest about 1.25 inches wide and 1 inch deep. Females lay two white eggs, incubated 15 to 18 days per Audubon, with young fledging after another 20 to 23 days. Costa's Hummingbirds can raise one to two broods in a season.

Population and Outlook

Despite its narrow habitat requirements, Costa's Hummingbird is not a species of conservation concern at present. Cornell's life history page cites a Partners in Flight global breeding population estimate of 3.4 million birds, with the species rated low conservation concern. The main long-term threat identified is "clearing of desert scrub for development and grazing," a habitat-loss pressure common to most true desert specialists rather than anything specific to this bird's biology.

Frequently Asked Questions

What does a Costa's Hummingbird look like?

Adult males have an iridescent purple crown and throat, with the gorget feathers flaring out past the sides of the head in a shape Cornell Lab compares to "an overgrown mustache." Females are greenish above with a white eyebrow stripe, a grayish cheek patch, and whitish underparts, with no throat patch at all.

How do you tell a Costa's Hummingbird from an Anna's Hummingbird?

Color and shape together. Anna's Hummingbird carries rose-pink to magenta iridescence across a full, connected hood over both crown and throat. Costa's runs purple instead of rose-pink, and the gorget flares outward past the sides of the head rather than lying flat. Costa's is also smaller than Anna's.

Where do Costa's Hummingbirds live?

Primarily the Sonoran and Mojave Deserts, with a shift toward coastal scrub habitat in the late spring. Increasing numbers now stay year-round in gardens and suburban areas where flowers are available across all four seasons rather than following the traditional desert-to-coast seasonal movement.

How does a Costa's Hummingbird survive in the desert?

Partly through torpor, a nightly state where its heart rate drops from a normal 500 to 900 beats per minute down to roughly 50 beats per minute, conserving energy through cold desert nights. It also forages across a wide range of desert-adapted flowering plants, needing an estimated 1,840 flower visits a day to meet its energy needs.