Costa's Hummingbird (Calypte costae): Complete Guide to the Desert's Purple-Crowned Jewel

Costa's Hummingbird is a compact, short-billed hummingbird with a distinctive stocky profile. The male is instantly recognizable if seen well; the female is subtler but learnable with practice. The species is closely related to Anna's Hummingbird (Calypte anna) --- the two share the genus Calypte --- and the two frequently coexist in southern California coastal and foothill areas, making their separation an important identification skill.

Male Appearance

The adult male Costa's Hummingbird is among the most visually striking hummingbirds in North America, and the gorget is the reason. A deep violet-purple covers the crown and throat, creating a seamless hood of iridescent color that, in good light, has an almost electric quality --- shifting between deep purple and brilliant violet with viewing angle. What makes the gorget truly unique is the elongated lateral extensions: the gorget feathers on either side of the throat are lengthened and flare outward and downward like long, curved "mustache" points or sideburns, creating a silhouette unlike any other North American hummingbird. The back and upperparts are green. The underparts are white to pale grayish. The tail is fairly short and slightly forked. The overall impression is of a small, compact bird wearing an extraordinary, oversized collar.

Female Appearance

Female Costa's Hummingbirds are among the plainer of the western hummingbirds --- grayish-white underparts with little or no buffy or rufous wash, green upperparts, and a pale whitish supercilium (eyebrow stripe) that is more prominent than in many related species. The throat is white with small dusky streaks; occasional violet feathers may appear. The tail is green centrally with grayish or whitish-tipped outer feathers --- the lack of rufous in the tail is a useful distinction from female Rufous, Allen's, and Broad-Tailed Hummingbirds. The overall color palette is muted and desert-toned, a pattern that echoes the bleached landscapes the species inhabits.

Juvenile Appearance

Juvenile Costa's resemble adult females in their first plumage. Young males begin developing violet crown and gorget feathers during their first summer and fall, sometimes showing scattered violet patches by late summer. Juveniles of both sexes show fine buffy scaling on the upperparts that fades after first molt. Juvenile males can be confused with juvenile Anna's at this stage --- the violet crown color (versus rose-red in Anna's) is the key indicator when visible.

Similar Species & How to Tell Them Apart

Anna's Hummingbird (Calypte anna): The most frequent confusion species. Key differences: Anna's male has rose-red (not purple) covering both crown and gorget; Anna's gorget lacks the extended flaring mustache points. Female Anna's is larger and slightly greener below with a small red spot on the throat (often present). Anna's also has a longer bill. Where both occur in southern California, the combination of size, bill length, and color tone separates them reliably.

Rufous Hummingbird (Selasphorus rufus): Male Rufous has a rufous back and orange-red gorget --- no overlap with Costa's male. Female Rufous has rufous flanks, which female Costa's almost entirely lacks. Range overlap occurs in southern California during migration.

Black-Chinned Hummingbird (Archilochus alexandri): Male Black-Chinned has a black-and-iridescent-purple gorget but lacks the purple crown of Costa's. Female Black-Chinned is very similar to female Costa's --- longer bill and slightly different head shape are the best field marks.

The Costa's Hummingbird has one of the most unusual and least migration-oriented life histories of any North American hummingbird. While most of the species' range is technically migratory or partially migratory, the patterns are complex, highly local, and in flux.

In the core Sonoran and Mojave Desert breeding areas, most birds arrive on breeding grounds by December or January --- making Costa's one of the earliest-arriving and earliest-nesting hummingbirds in North America. Peak breeding occurs February through April, timed to exploit the winter-blooming desert flora. Many birds then depart the hottest desert areas as summer heat intensifies (temperatures regularly exceed 110°F in the Sonoran Desert), moving to slightly cooler coastal California or higher elevation chaparral. Some birds winter along the coast of central and southern California, where they may overlap extensively with Anna's Hummingbirds.

The critical distinction from most migratory hummingbirds is that Costa's migration is not a hemispheric north-south movement tied to insect and flower phenology in temperate North America. Instead, it represents a within-range movement between breeding habitat and non-breeding refuge, shaped by desert heat avoidance rather than cold avoidance. In areas with year-round garden feeders and irrigated plants, this within-range movement is increasingly suppressed, and resident populations are developing.

Feeding Costa's Hummingbirds in desert environments requires attention to heat management --- the primary challenge of desert feeder maintenance:

Heat and nectar freshness: In the Sonoran and Mojave Deserts, summer temperatures can exceed 110°F (43°C). At these temperatures, nectar ferments and molds within 24--36 hours. During hot weather (above 90°F), change nectar every 1--2 days. In milder desert winters (Dec--April, when Costa's is actively nesting), every 3--4 days is adequate.

Shade placement: This is critical in desert gardens. Place feeders in afternoon shade --- east-facing or under a patio cover or shade structure. Morning sun is acceptable; prolonged afternoon sun will spoil nectar rapidly and can stress the birds at peak heat.

Feeder color and style: Costa's have short bills --- standard or slightly shallower port feeders work well. Wide-mouth, basin-style feeders are easier to clean thoroughly. The bright red color of most hummingbird feeders is sufficient attractant; dyed nectar is unnecessary.

Year-round commitment: If you want Costa's as year-round residents (increasingly possible with the species' expanding sedentary tendencies), maintain feeders consistently through summer with diligent twice-weekly cleaning and refilling. This investment is rewarded with a resident pair that comes to regard your garden as core territory.

Multiple feeders: Males are territorial. In desert gardens, placing two or three feeders around the property allows multiple birds to feed. Position one in a quieter corner shaded from the dominant male's primary perch view.

Explore the NectarBloom Hummingbird Trail for a complete guide to desert feeder placement, including seasonal maintenance calendars for Southwest gardens.

Costa's Hummingbird nests earlier than almost any other North American hummingbird --- a strategy that exploits the winter-spring bloom season of desert plants before summer heat arrives and resources diminish. In the low Sonoran Desert, nest construction can begin as early as December, with eggs laid in January through March. This is among the earliest nesting windows of any bird in the continental United States.

The nest is a small, compact cup placed in a desert shrub --- often an ocotillo arm, a cholla cactus branch, a palo verde fork, or a dense desert shrub --- typically at low heights (2--8 feet above ground). The nest is constructed of plant fibers, thistledown, plant material, and spider silk, decorated externally with bits of dried plant material that provide camouflage against the desert background. The low nest placement, surprising in a desert environment where terrestrial predators (coyotes, roadrunners, snakes) are common, may be a consequence of the limited available nest sites in open desert scrub.

Two white eggs are laid. Incubation lasts 15--17 days. Chicks fledge at 20--23 days. The female incubates alone and provides all parental care; males are uninvolved in nesting after mating. In favorable conditions, a female may raise two broods in the same season, with the second nest started while the first brood is still being fed after fledging.

Because nesting occurs during the coolest part of the desert year, thermal regulation for eggs and nestlings is not as challenging as it would be in summer --- but cold desert nights still require the female to brood closely. By the time chicks fledge in March or April, food availability is at or near annual peak, giving fledglings the best possible start.

Costa's Hummingbird is classified as Least Concern by the IUCN Red List. Breeding Bird Survey trends are difficult to assess precisely for this species because its desert habitat and early breeding season place it outside the core sampling windows of many survey protocols. However, there is no evidence of major population decline, and in some urban areas (Tucson, Phoenix, the Coachella Valley) populations appear to be stable or growing in response to garden feeder availability.

The primary conservation concerns for Costa's Hummingbird center on habitat quality in the Sonoran and Mojave Deserts --- both of which face pressure from utility-scale solar development, groundwater depletion affecting desert wash plant communities, and urban expansion at the desert fringe. Climate change is also a factor: while Costa's already lives at temperature extremes, continued warming may push the boundaries of heat tolerance and affect the timing and abundance of desert wildflower blooms.

Invasive buffelgrass (Pennisetum ciliare) is a significant threat to Sonoran Desert habitats --- this aggressive grass fuels intense fires that can kill saguaros and other desert plants that otherwise survive drought but not fire. Loss of native Sonoran plant communities reduces the nectar base that Costa's Hummingbirds depend on during the critical winter-spring breeding season.

Supporting Costa's Hummingbird at a practical level means: planting native Sonoran or Mojave Desert species in desert gardens (particularly winter-blooming plants like chuparosa and penstemon), maintaining clean, dye-free feeders year-round in desert environments, reducing pesticide use, and supporting organizations working to control buffelgrass and preserve native desert habitats.