The desert is a strange place to make a living on flowers, and yet the Costa’s Hummingbird has made it home. This is the hummingbird of the Sonoran and Mojave. It is a small, compact, hunched little bird that nests in late winter and feeds at ocotillo and chuparosa. Then it clears out before the worst of the summer heat arrives.
The male wears the most extravagant gorget in North America. A blaze of violet-purple covers his crown and throat, then flares backward into two long points, like an overgrown moustache trailing past his shoulders. And when he dives for a female, he does something with the sound of it that researchers only worked out in 2018.
Quick Facts
Scientific name: Calypte costae
Length: about 3 to 3.5 inches, with a wingspan around 4.3 inches
Weight: 2 to 3 grams, one of the lightest hummingbirds in North America
Range: Sonoran and Mojave Deserts, coastal southern California, Baja California, and northwestern Mexico
Named for: Louis Marie Pantaleon Costa de Beauregard, a Sardinian statesman, military commander, historian and amateur archaeologist, by French naturalist Jules Bourcier
Longevity record: a female of at least 8 years and 9 months, banded in California in 2001 and recaptured there in 2009
Population: around 3.4 million, fairly stable or slightly declining since 1968
Conservation status: Least Concern, rated 11 out of 20 on the Continental Concern Score
How to Identify a Costa’s Hummingbird
The male is unmistakable in good light. Brilliant violet-purple covers his crown and throat, and the gorget feathers extend backward and downward into a long point on each side of the neck. No other North American hummingbird has anything like it. His back is green, his wings and short tail dark, with white below the gorget.
In poor light the purple goes black, as all iridescent gorgets do, so a dark-hooded desert hummingbird is worth a second look as the bird turns.
The female is genuinely difficult, and honesty serves better than confidence here. She is greenish above and dingy greyish-white below, with a pale eyebrow that wraps around a darker cheek patch. About half of females show a small tuft of violet feathers in the centre of the throat, and the rest show none at all, so its absence proves nothing. She closely resembles female Anna’s and Black-chinned Hummingbirds, and separating them is one of the standard challenges of southwestern birding.
Structure is the best clue for both sexes. Costa’s is compact and dumpy with a hunched posture, and its tail is notably short. It is short enough that when the bird perches, the wings reach the tail tip or nearly so. The bill droops very slightly. That combination, small, hunched, short-tailed and droop-billed, separates it from the longer-tailed Anna’s and Black-chinned better than plumage does.
There is one more oddity. In most hummingbirds the male is the vocal one. In Costa’s it runs the other way: females call frequently in daily life, while males stay largely silent except when displaying or alarmed.
Similar Species
Anna’s Hummingbird is the closest relative, sharing the genus Calypte. Male Anna’s is rose-pink rather than violet, and his gorget does not flare into points. Anna’s is also larger, longer-tailed and less hunched. Anna’s and Costa’s hybrids occur, and can look confusingly intermediate.
Black-chinned Hummingbird males have only a thin violet band below a black chin, nothing like the Costa’s full purple hood. Females of the two are very similar, and the Costa’s shorter bill and tail help.
Calliope Hummingbird is smaller still, and the male’s magenta gorget forms separate streaming rays rather than a solid flared patch.
For more detail, the article on North American species sets out the whole cast, and the size extremes of the family put these tiny desert birds in context.
Range, Habitat, and the Desert Life
Costa’s occupies desert scrub across the Sonoran and Mojave Deserts, plus chaparral and coastal sage scrub in southern California, and extends south through Baja California and into northwestern Mexico. Washes, dry canyon bottoms, arroyos and the desert edges of suburbia are all good places to look. The Southwest guide covers where and when across that region.
The species solves the desert’s central problem, which is timing, by breeding in the cool part of the year and leaving before the heat peaks. In the Sonoran Desert, breeding runs from February to May. In the Mojave it stretches to June. In coastal California’s sage and chaparral it runs from March into September.
Once nesting finishes, many desert birds head west and north to coastal California and Baja, following flowers rather than enduring a Sonoran July. By high summer, Costa’s are genuinely hard to find around Tucson. They return in autumn as desert plants such as chuparosa come back into bloom.
That pattern is changing at the edges. Where suburban gardens provide flowers year-round, increasing numbers of Costa’s now stay put all year rather than moving seasonally.
One thing Costa’s does not do is follow the pattern of most other western hummingbirds, which climb into mountain meadows after breeding to catch the late-summer alpine bloom. Costa’s rarely moves upslope, heading for the coast instead.
The species also wanders far more than its desert reputation suggests, with records north to Alaska and British Columbia, east to Kansas, and south into Jalisco.
The Dive, and the Acoustic Trick
The male’s courtship display is a long, looping performance. He circles the perched female and dives past her in broad U-shaped arcs, sometimes continuing for up to four minutes, though about 35 seconds is more typical. Throughout, he produces a thin, extraordinarily high-pitched whistle that rises and falls in pitch, a sound familiar to anyone who has walked a desert wash in early spring.
Here is the remarkable part. Research by Christopher Clark and Emily Mistick, published in Current Biology in 2018, found that the male is not simply diving. He is managing what the female hears.
He dives to the side of her rather than straight at her. That minimises the Doppler shift which would otherwise reveal how fast he is actually travelling, the same effect that changes the pitch of an ambulance siren as it passes. At the same time he twists his tail vertically, by as much as 90 degrees, to aim the sound the feathers produce directly at her. Reports of the study put the gain at as much as 11 decibels.
In other words, he makes himself sound more impressive than his speed alone would warrant, while hiding the cue that would give the game away. Clark’s own summary of the insight is worth repeating. Once he realised the speed was not trivial for a scientist to measure, he realised it would not be trivial for a female to measure either.
The sound itself is made by the tail feathers rather than the voice, a mechanism called sonation, the same trick used by its sister species Anna’s. More on how hummingbirds produce sound, vocally and mechanically, is covered separately.
Surviving the Desert Night
Deserts are hot by day and genuinely cold after dark, and this bird lives in the hottest, driest conditions of any North American hummingbird. That made it the primary subject of foundational research into hummingbird torpor and heat economy in the 1960s.
The numbers from that work are startling. The heart of a torpid Costa’s Hummingbird beats about 50 times a minute. Awake and at rest, the same bird’s heart runs at 500 to 900 beats a minute. The bird effectively shuts itself down overnight and restarts in the morning.
That 50 beats a minute is the figure quoted for torpid hummingbirds generally, and it was measured in this species. The full physiology of torpor is covered separately, along with where hummingbirds spend the night.
Behavior and Breeding
For all the drama of the display, Costa’s is not an especially aggressive hummingbird. Males and females defend flower patches, but they are subordinate to larger species and tend to move around chasing blooms rather than holding one territory against all comers.
Males mate with multiple females and provide no care afterward. The female builds a small cup of plant fibres and down, sometimes bound with spider silk and finished with lichen. It sits low, typically three to seven feet up, often on a yucca stalk or in a palo verde, ironwood, cholla or acacia. Construction takes four or five days.
She lays two white eggs, incubates them for 15 to 18 days, and the young fledge 20 to 30 days after hatching. She may raise one or two broods in a season. The full breeding cycle is covered separately, and how long the survivors live is a separate question again.
Their diet is nectar plus small flying insects taken in midair, with ocotillo and chuparosa among the most important desert nectar sources. To put the demand in perspective, Cornell calculates that a Costa’s Hummingbird must visit around 1,840 flowers in a day to meet its energy needs. More on the balance between nectar and insects is covered separately.
Conservation
Costa’s Hummingbirds are relatively common. Breeding Bird Survey data show the population fairly stable or slightly declining between 1968 and 2019. Partners in Flight estimates 3.4 million birds and rates the species 11 out of 20 on the Continental Concern Score, which places it as a species of low conservation concern.
The biggest threat is the clearing of desert scrub for development and grazing. That is a habitat problem rather than a climate one, and it is local and specific in a way that makes it tractable.
Attracting Costa’s Hummingbirds
If you live within their range, especially in desert-edge suburbia, they come readily to gardens and feeders.
Plant desert natives, with chuparosa, ocotillo and desert willow among the best, and keep a clean feeder available. Put feeders out unusually early, since these birds are breeding while much of the country is still in winter. And because the species increasingly stays year-round where flowers persist, a garden with something always in bloom may hold them permanently.
The guide to attracting hummingbirds covers planting and placement. The nectar recipe and feeder care page covers what goes in the feeder and how often to clean it. For local timing, see when to put feeders out and take them down.
Frequently Asked Questions
How do I identify a Costa’s Hummingbird?
Males have a violet-purple crown and throat with gorget feathers flaring into long points on each side. Both sexes are small, compact and hunched, with a notably short tail and a slightly drooping bill.
How do I tell a female Costa’s from a female Anna’s or Black-chinned?
It is genuinely hard. Look for the Costa’s smaller size, shorter bill, shorter tail, paler belly, and the pale eyebrow wrapping around a dark cheek. About half of females show a small violet throat tuft, but its absence proves nothing.
Where do Costa’s Hummingbirds live?
Desert scrub in the Sonoran and Mojave Deserts, chaparral and coastal sage scrub in southern California, Baja California, and northwestern Mexico.
When is the best time to see one?
February through May in the Sonoran Desert, and into June in the Mojave. By high summer most have left the desert for cooler coastal areas.
What is the high-pitched whistle in the desert in spring?
Very likely a displaying male Costa’s. The sound is produced by his tail feathers during his diving display, not by his voice.
How do they survive cold desert nights?
By entering torpor. A torpid Costa’s heart beats about 50 times a minute, against 500 to 900 when the bird is awake and resting.
Do Costa’s Hummingbirds migrate?
Many move seasonally between desert breeding areas and coastal California or Baja, though increasing numbers now stay year-round where suburban gardens flower continuously.
Conclusion
The Costa’s Hummingbird is a study in doing more with less. A two to three gram bird makes a living in the driest country on the continent, timing its whole breeding year around the heat. It visits nearly two thousand flowers a day to stay aloft, then shuts its heart down to fifty beats a minute to get through the night. Then, when it comes time to impress a female, it engineers the acoustics of its own dive so it sounds better than it is. There is nothing modest about that purple moustache, and on the evidence, nothing modest about the bird either.
Quiz: The Costa’s Hummingbird
The quiz questions are grounded in peer-reviewed research and authoritative species accounts. Key references are listed below:
The study showing that male Costa’s Hummingbirds dive to the side of the female to minimize the Doppler shift that would reveal their true speed, while twisting their tail feathers to aim the sound at her and amplify it by as much as 11 decibels.
Describes the male’s gorget flaring along the sides of the neck like an overgrown mustache, the species’ small compact build and hunched posture, and the short tail that barely meets the wings when perched.
Source for measurements, desert and sage scrub habitat, and how female Costa’s differ from female Anna’s and Black-chinned by size, bill length, tail length, and belly color.
Regional breeding seasons across the Sonoran Desert, Mojave Desert, and coastal California, the importance of chuparosa and ocotillo, and the species’ departure from the desert between mid-June and October.
Details clutch size, incubation and fledging periods, the female’s variable violet throat tuft, and the unusual pattern of females vocalizing frequently while males stay largely silent outside display.
Covers separation from Anna’s Hummingbird by gorget flare and iridescence color, the narrower outer tail feather, documented hybridization between the two species, and the male’s whistled display vocalizations.