Hummingbirds are the only birds that have adapted to fly backward and forward. Their wings can beat incredibly fast. In fact, when hummingbirds hover, their wings can beat from 22 to 72 times per second. This rapid motion causes them to expend most of their energy in flight; to make up for this nutritional deprivation hummingbirds can consume half of their body weight in food per day. Most species of hummingbird migrate during seasonal changes; however, Anna's and Allen's hummingbirds are the only two species that remain in the United States and Canada year-round. Calypte anna is the largest hummingbird that inhabits the west coast.
Perception Channels: visual ; tactile ; acoustic ; chemical
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.
(Kaufman 1996)
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
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.
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 )
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 )
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
Anna's hummingbirds live an average of 8.5 years.
Range lifespan
Status: wild: 8.5 (high) years.
Average lifespan
Status: wild: 8.5 years.
Average lifespan
Status: wild: 98 months.
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.
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.
Known Predators:
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)
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.
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)
Anna's hummingbird (Calypte anna) is a medium-sized bird species of the family Trochilidae. It was named after Anna Masséna, Duchess of Rivoli.
It is native to western coastal regions of North America. In the early 20th century, Anna's hummingbirds 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, allowing the species to expand its breeding range. Year-round residence of Anna's hummingbirds in the Pacific Northwest is an example of ecological release dependent on acclimation to colder winter temperatures, introduced plants, and human provision of nectar feeders during winter.
These birds feed on nectar from flowers using a long extendable tongue. They also consume small insects and other arthropods caught in flight or gleaned from vegetation.
Anna's hummingbird was formally described and illustrated in 1829 by the French naturalist René Lesson in his Histoire naturelle des Oiseaux-Mouches from a specimen that had been collected in California. Lesson placed it in the genus Ornismya and coined the binomial name Ornismya anna.[2][3] Anna's hummingbird is now placed in the genus Calypte that was introduced in 1856 by the English ornithologist John Gould.[4][5] Gould did not explain the derivation of the genus name but it is probably from the Ancient Greek kaluptrē meaning "woman’s veil" or "head-dress" (from kaluptō meaning "to cover"). The specific epithet anna was chosen to honour Anne d'Essling who married the ornithologist François Victor Massena, 3rd Duke of Rivoli.[6] The species is monotypic: no subspecies are recognised.[5]
Anna's hummingbirds are 3.9 to 4.3 in (9.9 to 10.9 cm) long with a wingspan of 4.7 inches (12 cm) and a weight range of 0.1 to 0.2 oz (2.8 to 5.7 g).[7] They have an iridescent bronze-green back, a pale grey chest and belly, and green flanks. Their bills are 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. Females also have iridescent red gorgets, although they are usually smaller and less brilliant than the male.[7]
The male Anna's hummingbird is the only North American hummingbird species with a red crown.[7][8] 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.[8]
The male has a striking reddish-pink crown and gorget, which are strongly iridescent and dependent on the angle of illumination and observation by female or male competitor birds.[8] The iridescence results from large stacks of melanosomes in the feather barbules, occurring as layers separated by keratin.[8] The barbules reflect incident light in the manner of partially-opened Venetian blinds, enabling the iridescence – which varies the head and gorget coloration with the changing angle of light – as a coloration advantage for courtship attraction and territory defense.[8]
Male birds with elevated levels of protein in their diet have more colorful crowns and higher iridescence in their head feathers compared with male birds with low protein intake.[9]
The male's call – scratchy and metallic – is typically used as the bird perches in trees and shrubs.[7] Anna's hummingbirds have adapted to urban environments and are commonly seen in backyards and parks, and at feeders and flowering plants. Anna's hummingbirds eat flying insects.[10]
According to a 2021 estimate, there are 8 million Anna's hummingbirds in the western United States and Canada,[11] with the population increasing since 1970.[12] As of 2021, the International Union for Conservation of Nature Red List of Threatened Species lists the Anna's hummingbird among species of least concern.[1]
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.[7][13] They tend to be permanent residents within their range. However, birds have been spotted far outside their range in such places as southern Alaska, Saskatchewan, New York, Florida, Louisiana, and Newfoundland.[14][15]
In response to rising temperatures at low elevations during climate change in the 21st century, Anna's hummingbirds have expanded their range into the cooler summer environments of higher-altitude (up to 2,825 metres (9,268 ft)) mountainous terrains of California, such as the Sierra Nevada.[16]
Anna's hummingbirds have the northernmost year-round range of any hummingbird. Birds have been recorded in Alaska as early as 1971, and resident in the Pacific Northwest since the 1960s, particularly increasing as a resident population during the early 21st century.[17][18] Scientists estimate that some birds overwinter and presumably breed at northern latitudes where food and shelter are available throughout winter, tolerating moderately cold winter temperatures.[17][18]
During cold temperatures, Anna's hummingbirds gradually gain weight during the day as they convert sugar to fat.[19][20]
While their range was originally limited to the chaparral of California and Baja California, it expanded northward to Oregon, Washington, and British Columbia, and east to Arizona in the 1960s and 70s.[17] This rapid expansion is attributed to the widespread planting of non-native species, such as eucalyptus, as well as the use of urban bird feeders, in combination with the species' natural tendency for extensive postbreeding dispersal.[7]
In the Pacific Northwest, the fastest growing populations occur in regions with breeding-season cold temperatures similar to those of its native range.[17] Northward expansion of the Anna's hummingbird represents an ecological release associated with introduced plants, year-round nectar availability from feeders supplied by humans, milder winter temperatures possibly associated with climate change, and acclimation of the species to a winter climate cooler than its native region.[17][18] Although quantitative data are absent, it is likely that a sizable percentage of Anna's hummingbirds in the Pacific Northwest still do migrate south for winter, as of 2017.[18]
Anna's hummingbirds with inadequate stores of body fat or insufficient plumage are able to survive periods of subfreezing weather by lowering their metabolic rate and entering a state of torpor.[16][21]
When studied in colder temperatures at mountainous elevations, Anna's hummingbirds used torpor more frequently than at lower elevations.[16]
While collecting nectar, the Anna's hummingbird assists in plant pollination.[12] There is evidence that Anna's hummingbirds in flight generate an electrostatic charge that adheres pollen to their beaks and feathers, facilitating transfer of pollen grains to hundreds of flowers per day while foraging for nectar.[22] This species sometimes consumes tree sap.[23]
Anna's hummingbirds can shake their bodies 55 times per second to shed rain while in flight, or in dry weather, to remove pollen or dirt from feathers.[24] Each twist lasts four-hundredths of a second and applies 34 times the force of gravity on the bird's head.[24]
During hovering flight, Anna's hummingbirds maintain high wingbeat frequencies accomplished by their large pectoral muscles via recruitment of motor units.[25] The pectoral muscles that power hummingbird flight are composed exclusively of fast glycolytic fibers that respond rapidly and are fatigue-resistant.[25]
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. When a female flies onto a male's territory, the male rises up about 130 ft (40 m) before diving over the female. As the male approaches the bottom of the dive, it reaches an average speed of 27 m/s (89 ft/s), which is 385 body lengths per second.[26] At the bottom of the dive, the male travels 23 m/s (51 mph), and produces an audible sound produced by the tail feathers, described by some as an "explosive squeak".[27][28]
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 camouflaged with chips of lichen, plant debris, and occasionally urban detritus such as paint chips and cigarette paper.[13] The nest materials are bound together with spider silk. They are known to nest as early as mid-December and as late as June, depending on geographic location and climatic conditions.[7][29]
Anna's hummingbirds may hybridize with other species, especially the congeneric Costa's hummingbird.[13] 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.[30]
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.[31] It was later determined to be a hybrid between an Anna's hummingbird and a black-chinned hummingbird.[32][33]
In the 2017 Vancouver Official City Bird Election, Anna's hummingbird was named the official bird of the city of Vancouver, British Columbia.[34] Anna's hummingbirds are non-migrating residents of Seattle where they live year-round through winter, enduring extended periods of subfreezing temperatures, snow, and high winds.[35]
Female feeding
A female
A male
Adult male
A juvenile
.jpg)
Female in California
Feeding, Vancouver Island
Anna's hummingbird (Calypte anna) is a medium-sized bird species of the family Trochilidae. It was named after Anna Masséna, Duchess of Rivoli.
It is native to western coastal regions of North America. In the early 20th century, Anna's hummingbirds 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, allowing the species to expand its breeding range. Year-round residence of Anna's hummingbirds in the Pacific Northwest is an example of ecological release dependent on acclimation to colder winter temperatures, introduced plants, and human provision of nectar feeders during winter.
These birds feed on nectar from flowers using a long extendable tongue. They also consume small insects and other arthropods caught in flight or gleaned from vegetation.
