Anna's Hummingbird (Calypte anna) is a year-round resident along the Pacific coast of North America, breeding north to British Columbia and east to Arizona. These hummingbirds are abundant in open woodlands, chapparal, scrubby areas, and partly open situations, as well as in deserts, especially in winter. They often forage in gardens and parks. They ascend to montane regions in the summer postbreeding season to forage in high mountain meadows.
Nesting may begin in December. In the male's courtship display, he hovers in mid-air giving a buzzy song, then flies much higher before diving steeply and rapidly toward the female, making a loud explosive popping sound at the bottom of his dive. He may also buzz back and forth in front of the perched female in short flights. Detailed analyses of male displays revealed that after powering the initial stage of the dive by flapping, males folded their wings by their sides, at which point they reached an average maximum velocity of 385 body lengths. This is the highest length-specific velocity known for any vertebrate. They then spread their wings to pull up and experienced centripetal accelerations nearly nine times greater than gravitational acceleration. This acceleration is the highest reported for any vertebrate undergoing a voluntary aerial maneuver, with the exception of jet fighter pilots. Displaying Anna's Hummingbird males produce both a vocal song and a dive-sound (made with the wings and outermost tail feathers) that sounds similar to a portion of the song, an intriguing observation discussed by Clark and Feo (2010).
The nest of an Anna's Hummingbird, which is relatively large for a hummingbird nest, is usually constructed on a branch of a tree or shrub, but may also be in vines, on wires, or under eaves. It is typically 1 to 8 m above the ground. Built by the female alone,it is a cup of plant fibers and spider webs. It is lined with fine plant down (and sometimes feathers) and the outside is camouflaged with lichens. The female may continue building after eggs are laid. The female incubates the 2 (rarely 1 or 3) white eggs by herself for 14 to 19 days. The young are fed by the female and take their first flight at around 18 to 23 days.
Anna's Hummingbird is very common over much of its range and has adapted well to suburban areas.
(Kaufman 1996; AOU 1998; Clark 2009; Clark and Feo 2010)
Male Anna's hummingbirds are easily recognized by their crimson crown (top of head) and gorget (throat). The tail is dark, the belly is greyish white, and the back is iridescent green as in most hummingbirds. Females and immatures lack the crimson crown and show varying degrees of red spotting on the throat. The tips of their tail feathers are white. Females and immatures of most hummingbird species are very difficult to tell apart, and field identification is often impossible.
This beautiful little bird occurs along the western edge of North America from southern Alaska to northwestern Mexico. Like other hummingbirds, Anna's is a skilled flyer that can hover in the air and fly backwards. It has a typical long, slender bill which it uses to feed on nectar, pollen, and insects. It often catches insects in flight, and it will stick out its long, skinny tounge during and after feeding.
Calypte anna breeds along the western coast of North America. The breeding range stretches from British Columbia through Arizona to the western edge of New Mexico. However, the non-breeding range is expanding. This range extends from the Alaskan coast to northern Mexico.
Biogeographic Regions: nearctic (Native )
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: BREEDS: western Washington, western Oregon, California (west of Sierra; Humboldt and Tehama counties south), northwestern Baja California, and southern Arizona (north to Phoenix, Superior). Most breeding occurs in California. May breed in southwestern British Columbia and western Texas. WINTERS: southwestern Oregon to central Baja, east to southern Arizona, northern Sonora, northern Chihuahua.
Anna's hummingbirds are medium sized, stocky hummingbirds. They are sexually dimorphic. Males and females both have a bronzy, green dorsal area that is glossy in appearance and a dull, gray ventral region. They have a medium length bill and a broad tail. Male C. anna have a brightly colored rose throat area and crown and a dark tail. Females are generally a dull mixture of gray/white or gray/brown, but may have a patch of metallic red or purplish feathers in the center of the throat area. The tail, tipped with white, is metallic green in the center with the exterior tail feathers darkening to black. Juvenile male and female birds both resemble adult females but there are some slight variations. Immature males have brightly colored feathers on the throat and crown and a less rounded tail, while young females are a pale brown and possess no metallic colored feathers on the throat region.
Range mass: 4 to 4.5 g.
Average length: 100 mm.
Range wingspan: 114 to 121 mm.
Other Physical Features: endothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: sexes colored or patterned differently; male more colorful
Average basal metabolic rate: 0.1175 W.
Length: 10 cm
Weight: 4 grams
Calypte anna have made their home in open woods, shrubs, gardens, and parks. During breeding season they are restricted to California and a habitat separation is established between males and females. During this time males typically move to more open habitats including canyon sides and hill slopes. Females, on the other hand, live in trees, including evergreens and oaks. Anna's Hummingbirds also experience different habitats with the changing seasons. During the summer months they move to higher elevations, and in winter they move to lower altitudes.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest ; scrub forest
Other Habitat Features: urban ; suburban ; agricultural
Habitat and Ecology
Comments: Open woodland, chaparral, scrubby areas, partly open situations, and gardens, foraging also in meadows, ascending to montane regions in summer postbreeding season (AOU 1983). Nests in tree, vine, shrub, or artificial substrate in wide variety of locations, from <1 to about 9 m above ground.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
May ascend to montane regions in summer after breeding. Unusual among hummingbirds in remaining in U.S. in winter.
Calypte anna has four sources of food: nectar from flowers, sap from trees, sugar-water mixes from feeders, and very small insects and spiders. Anna's hummingbirds are equipped with long, narrow bills and have a body adapted to hover over flowers. These two features allow them to easily extract nectar. While the bird is hovering over the flower it extends its tongue and inserts it into the flower. Calypte anna is most attracted to long, tubular flowers, with a red, orange, or violet hue. Some common hummingbird flowers include: azaleas (Rhododendron arborescens), fuchsia (Fuchsia arborescens), scarlet morning glory, honeysuckle (Lonicera sempervirens), and impatiens (Impatiens balsamina). However, C. anna feeds most frequently on: chaparral current (Ribes malvaceum), fuchsia-flowered gooseberry (Ribes speciosum), great-berried manzanita (Arctostaphylos glauca), monkey-flower (Diplacus longiforus), pitcher-sage (Salvia spathacea), California fuchsia (Epilobium), western columbine (Aquilegia formosa), and Indian warrior (Pedicularis densiflora). Apart from flowers, Anna's hummingbirds find food in the air by capturing flying insects or eating insects trapped in spider webs. They also use holes in trees to extract sap.
Animal Foods: insects
Plant Foods: nectar; pollen; sap or other plant fluids
Primary Diet: herbivore (Nectarivore )
Comments: Feeds on nectar, tree sap (e.g., at sapsucker holes), and small insects and spiders (caught in air; gleaned from tree trunks). Nectar sources include EUCALYPTUS, NICOTIANA, AGAVE, CASTILLEJA, DIPLAUCUS, SILENA, RIBES, ARCTOSTAPHYLOS, etc.
Calypte anna has many predators including western scrub-jays (Aphelocoma californica), American kestrels (Falco sparverius), greater roadrunners (Geococcyx californianus), and curved-billed thrashers (Toxostoma curvirostre). As a response to these predators, C. anna has developed two primary defense mechanisms. First, when a predator attacks a nest the female will mob the assailant. She will do this by hovering in front of the invader, beating her wings rapidly, and attacking the head and back. The second mechanism is to avoid low lying food sources, C. anna prefer high feeders and flowers.
- western scrub-jays (Aphelocoma californica)
- American kestrels (Falco sparverius)
- greater roadrunners (Geococcyx californianus)
- curved-billed thrashers (Toxostoma curvirostre)
Males occupy territories for extended period; territories not necessarily related to food supply and quality (Powers 1987). Apparently has close coevolutionary relationship with RIBES SPECIOSUM (Stiles 1972).
Life History and Behavior
Perception Channels: visual ; tactile ; acoustic ; chemical
Anna's hummingbirds live an average of 8.5 years.
Status: wild: 8.5 (high) years.
Status: wild: 8.5 years.
Status: wild: 98 months.
Lifespan, longevity, and ageing
Male and female C. anna only come together to mate. Females are responsible for building nests, incubating the young, and rearing the brood. The seasonal winter rains start mating season, and it is during this time that males move into their breeding territories and females start the nest building process. The nest is bound together with spider webs and is lined with soft material such as plants, feathers, or hair. The outside of the nest is draped with bark, dead leaves, lichen, or paint chips, in an attempt to camouflage. The actual mating ritual commences when a female enters a male's territory. After the male spots the female he does a series of dives in the air and begins to chase her. During this chase, the female leads the male toward her nesting area and perches. During copulation the female spreads her tail, twisting it slightly downward and to the side. In order for fertilization to occur, the male must mount her back. During this time, he may seize her crown feathers with his bill and twist his abdomen and tail down her side. Copulation lasts 3 to 5 seconds.
Mating System: polygynandrous (promiscuous)
The breeding season commences between November and December and continues until sometime between April and May. During this season C. anna can have two broods. Each brood consists on average of 2 white, elliptical eggs, which are laid one day apart. Females incubate the eggs for 14-19 days, and chicks are in the nest an additional 18 to 23 days. The hatchlings are altricial, barely resembling the adult form. Their eyes open on the fifth day after hatching. When the hatchlings are six days old they are fully covered with down. After the nesting period the young remain dependent on the mother for a few additional days, but within one or two weeks they achieve total independence. There is no male parental care. Interestingly, immature C. anna start to show territorial behavior when they are quite young. After leaving the nest, Anna's hummingbirds have a tendency to remain in pairs, usually siblings. However, by fall most young C. anna separate and maintain their own territory.
Breeding interval: There may be two broods produced per breeding season
Breeding season: The breeding season commences between November and December and continues until sometime between April and May.
Average eggs per season: 2.
Range time to hatching: 14 to 19 days.
Range fledging age: 18 to 23 days.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average eggs per season: 2.
Female Anna's hummingbirds incubate and feed their young until they reach independence. There is no male parental care.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)
Breeding begins in late December. Clutch size is 2. Incubation, by female, lasts 14-19 days. Young are tended by female, leave nest in 18-26 days, independent in 1-2 weeks. Priduces two broods annually in many areas (Johnsgard 1983).
Molecular Biology and Genetics
Barcode data: Calypte anna
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Calypte anna
Public Records: 5
Specimens with Barcodes: 8
Species With Barcodes: 1
The Anna's Hummingbird population has been spreading and growing since the 1950's. They have expanded north and east from their original habitat. The flowers and feeders of suburban gardens have enabled them to extend into these different regions. Calypte anna are very common within most of their range; thus, there are regular sightings. In addition, they adapt well to suburban areas.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N3 - Vulnerable
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Relevance to Humans and Ecosystems
There are no negative impacts of Anna's hummingbirds.
Pollinates many species of flowers, such as the chaparral flora of California. The chaparral flora has a large variety of species that have adapted to Anna's hummingbirds. These species of plants have developed winter growth and flowering to fit the breeding and feeding patterns of C. anna. These species, along with others, have evolved directly alongside Anna's hummingbirds.
Anna's hummingbird (Calypte anna) is a medium-sized stocky hummingbird native to the west coast of North America. This bird was named after Anna Masséna, Duchess of Rivoli. In the early 20th century, Anna's hummingbird bred only in northern Baja California and southern California. The transplanting of exotic ornamental plants in residential areas throughout the Pacific coast and inland deserts provided expanded nectar and nesting sites, and the species was able to expand its breeding range greatly.
Anna's hummingbird is 3.9 to 4.3 in (9.9 to 10.9 cm) long. It has an iridescent bronze-green back, a pale grey chest and belly, and green flanks. Its bill is long, straight and slender. The adult male has an iridescent crimson-red derived from magenta to a reddish-pink crown and gorget, which can look dull brown or gray without direct sunlight, and a dark, slightly forked tail. Female Anna's hummingbirds also have iridescent red gorgets, though they are usually smaller and less brilliant than the males'. Anna's is the only North American hummingbird species with a red crown. Females and juvenile males have a dull green crown, a grey throat with or without some red iridescence, a grey chest and belly, and a dark, rounded tail with white tips on the outer feathers.
These birds feed on nectar from flowers using a long extendable tongue. They also consume small insects and other arthropods caught in flight or glean from vegetation. A PBS documentary shows how Anna's hummingbirds eat flying insects. They aim for the flying insect, then open their beaks very wide. That technique has a greater success rate than trying to aim the end of a long beak at the insect. On rare occasions, bees and wasps may become impaled on the bill of an Anna's hummingbird, causing the bird to starve to death.
While collecting nectar, they also assist in plant pollination. This species sometimes consumes tree sap. The male's call is scratchy metallic, and it perches above head-level in trees and shrubs.  They are frequently seen in backyards and parks, and commonly found at feeders and flowering plants.
A recent study  found that the Anna's hummingbird can shake their bodies 55 times per second while in flight. This shimmy, when done in dry weather, can shake off pollen or dirt from their feathers similar to how a wet shake by a dog removes water. This rate of shaking is the fastest of any vertebrate on earth.
Open-wooded or shrubby areas and mountain meadows along the Pacific coast from British Columbia to Arizona make up C. anna's breeding habitat. The female raises the young without the assistance of the male. The female bird builds a nest in a shrub or tree, in vines, or attached to wires or other artificial substrates. The round, 3.8-to-5.1-centimetre (1.5 to 2.0 in) diameter nest is constructed of plant fibers, downy feathers and animal hair; the exterior is camouflageed with chips of lichen, plant debris, and occasionally urban detritus such as paint chips and cigarette paper. The nest materials are bound together with spider silk. They are known to nest as early as mid-December and as late as June.
Unlike most northern temperate hummingbirds, the male Anna's hummingbird sings during courtship. The song is thin and squeaky, interspersed with buzzes and chirps, and is drawn to over 10 seconds in duration. During the breeding season, males can be observed performing an aerial display dive over their territories. The males also use the dive display to drive away rivals or intruders of other species. When a female flies onto a male's territory, he rises up approximately 130 ft (40 m) before diving over the recipient. As he approaches the bottom of the dive the males reach an average speed of 27 m/s (89 ft/s), which is 385 body lengths per second. At the bottom of the dive the male travels 23 m/s (51 mph), and produces a loud sound described by some as an "explosive squeak" with his outer tail-feathers.
Anna's hummingbirds hybridize fairly frequently with other species, especially the congeneric Costa's hummingbird. These natural hybrids have been mistaken for new species. A bird, allegedly collected in Bolaños, Mexico, was described and named Selasphorus floresii (Gould, 1861), or Floresi's hummingbird. Several more specimens were collected in California over a long period, and the species was considered extremely rare. It was later determined that the specimens were the hybrid offspring of an Anna's hummingbird and an Allen's hummingbird. A single bird collected in Santa Barbara, California, was described and named Trochilus violajugulum (Jeffries, 1888), or Violet-throated Hummingbird. It was later determined to be a hybrid between an Anna's hummingbird and a black-chinned hummingbird.
Anna's hummingbirds are found along the western coast of North America, from southern Canada to northern Baja California, and inland to southern and central Arizona, extreme southern Nevada and southeastern Utah, and western Texas. They tend to be permanent residents within their range, and are very territorial. However, birds have been spotted far outside their range in such places as southern Alaska, Saskatchewan, New York, Florida, Louisiana and Newfoundland.
Anna's hummingbirds have the northernmost year-round range of any hummingbird. During cold temperatures, Anna's hummingbirds gradually gain weight during the day as they convert sugar to fat. In addition, hummingbirds with inadequate stores of body fat or insufficient plumage are able to survive periods of sub-freezing weather by lowering their metabolic rate and entering a state of torpor.
There are an estimated 1.5 million Anna's hummingbirds. Their population appears to be stable, and they are not considered an endangered species.
- BirdLife International (2012). "Calypte anna". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- Williamson, Sheri (2001). A Field Guide to Hummingbirds of North America. New York, NY: Houghton Mifflin Harcourt. p. 199. ISBN 0-618-02496-4.
- "Anna's Hummingbird". Retrieved 2014-06-18.
- Hummingbirds: Magic in the Air (Video: Expert Hunters). Public Broadcasting Service. January 10, 2010. Video: Full Episode (at 16:45)
- "Anna's Hummingbird". Retrieved 2014-06-18.
- Peterson, Roger Tory; Peterson, Virginia Marie (1990). Peterson's Field Guide to Western Birds. Boston: Houghton Mifflin. pp. 216–217. ISBN 0-395-51424-X.
- "Anna's Hummingbird". Retrieved 2014-06-18.
- Study to be published in an upcoming edition of the Journal for Biomechanics of Flight
- "Hummingbird speediest shaker among vertebrates". ANI News. September 4, 2013. Retrieved July 4, 2013.
- Clark, C.J. (2009). "Courtship dives of Anna's hummingbird offer insights into flight performance limits". Proceedings of the Royal Society B 276 (1670): 3047–3052. doi:10.1098/rspb.2009.0508. PMC 2817121. PMID 19515669.
- Clark, C.J.; Feo, TJ (2008). "The Anna's Hummingbird chirps with its tail: a new mechanism of sonation in birds". Proceedings of the Royal Society B 275 (1637): 955–62. doi:10.1098/rspb.2007.1619. PMC 2599939. PMID 18230592.
- Yollin, Patricia (2008-02-08). "How hummingbirds chirp: It's all in the tail". San Francisco Chronicle. Retrieved 2008-02-08.
- Palmer, T.S. (September 1928). "Notes on persons whose names appear in the nomenclature of California birds". The Condor 30 (5): 277. doi:10.2307/1363227.
- Ridgway, Robert (1892). The Humming Birds. Washington DC: Smithsonian Institution. pp. 331, 329.
- Taylor, Walter P. (1909). "An instance of hybridization in hummingbirds, with remarks on the weight of generic characters in the Trochilidae". The Auk 26 (3): 291–293. doi:10.2307/4070800.
- Ridgway, Robert (1909). "Hybridism and generic characters in the Trochilidae". The Auk 26 (4): 440–442. doi:10.2307/4071292. Retrieved 2008-11-11.
- "Unusual Hummingbird for Idaho: Anna's Hummingbird - Calypte anna". Retrieved 2008-11-12.. See distribution map on bottom of page.
- "Pacific hummingbird found in eastern NFLD". CBC News. 2011-01-24. Retrieved 2011-02-03..
- Beuchat, C.A.; Chaplin, S.B.; Morton, M.L. (1979). "Ambient temperature and the daily energetics of two species of hummingbirds, Calypte anna and Selasphorus rufus". Physiol. Zool. 52: 280–295.
- Powers, D. R. (1991). "Diurnal Variation in Mass, Metabolic Rate, and Respiratory Quotient in Anna's and Costa's Hummingbirds". Physiological Zoology 64 (3): 850–870. JSTOR 30158211.
- Russell, S.M. (1996). Anna's Hummingbird (Calypte anna). In The Birds of North America, No. 226 (A. Poole and F. Gill, eds). The Academy of Natural Sciences, Philadelphia, and The American Ornithologists' Union, Washington DC
Names and Taxonomy
Comments: Some authors merge Calypte in Archilochus (AOU 1983).