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Calypte annaAnna's hummingbird

By Abigail Lobas

Geographic Range

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. (Russell, 1996)

Habitat

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. (Johnsgard, 1997; Russell, 1996)

Physical Description

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. (True, 1983; Unitt, 2000)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • male more colorful
  • Range mass
    4 to 4.5 g
    0.14 to 0.16 oz
  • Average length
    100 mm
    3.94 in
  • Range wingspan
    114 to 121 mm
    4.49 to 4.76 in
  • Average basal metabolic rate
    0.1175 W
    AnAge

Reproduction

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. (Russell, 1996; True, 1993)

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. (Russell, 1996; True, 1983)

  • 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
  • Average eggs per season
    2
    AnAge
  • 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

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

Lifespan/Longevity

Anna's hummingbirds live an average of 8.5 years. (Russell, 1996; True, 1983)

  • Range lifespan
    Status: wild
    8.5 (high) years
  • Average lifespan
    Status: wild
    8.5 years
  • Average lifespan
    Status: wild
    98 months
    Bird Banding Laboratory

Behavior

Anna's hummingbirds are not social animals; they are territorial and will dive at anything that enters their territory, no matter what size. These birds migrate between summer and winter ranges. They are active during the day and may become torpid at night to conserve energy. (Russell, 1996; True, 1993)

Communication and Perception

Food Habits

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. (Russell, 1996; True, 1983)

  • Animal Foods
  • insects
  • Plant Foods
  • nectar
  • pollen
  • sap or other plant fluids

Predation

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. (Russell, 1996; True, 1983)

Economic Importance for Humans: Positive

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. (True, 1983)

Economic Importance for Humans: Negative

There are no negative impacts of Anna's hummingbirds.

Conservation Status

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) (Kaufman, 1996)

Other Comments

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.

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Abigail Lobas (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nectarivore

an animal that mainly eats nectar from flowers

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

urban

living in cities and large towns, landscapes dominated by human structures and activity.

visual

uses sight to communicate

References

Johnsgard, P. 1997. The Hummingbirds of North America. London: Christopher Helm.

Kaufman, K. 1996. Lives of North American Birds. New York, New York: Houghton Mufflin Company.

Russell, S. 1996. Anna's hummingbird : Calypte anna No. 226. F Gill, ed. Birds of North America. Philadelphia: American Ornithologists' Union; Academy of Natural Sciences.

True, D. 1983. Hummingbirds of North America. Washington D.C.: Smithsonian Institution Press.

True, D. 1993. Hummingbirds of North America: Attracting, feeding, and Photographing. Albuquerque: University of New Mexico Press.

Unitt, P. 2000. "Ocean Oasis: Calypte anna" (On-line). Accessed March 21, 2001 at http://www.oceanoasis.org/fieldguide/caly-ann.html.

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