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 (True, 1983; Unitt, 2000)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.
Female Anna's hummingbirds incubate and feed their young until they reach independence. There is no male parental care.
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)
Rhododendron arborescens), fuchsia (Fuchsia arborescens), scarlet morning glory, honeysuckle (Lonicera sempervirens), and impatiens (Impatiens balsamina). However, 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)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. is most attracted to long, tubular flowers, with a red, orange, or violet hue. Some common hummingbird flowers include: azaleas (
Aphelocoma californica), American kestrels (Falco sparverius), greater roadrunners (Geococcyx californianus), and curved-billed thrashers (Toxostoma curvirostre). As a response to these predators, 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, prefer high feeders and flowers. (Russell, 1996; True, 1983)has many predators including western scrub-jays (
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 (True, 1983). These species, along with others, have evolved directly alongside Anna's hummingbirds.
There are no negative impacts of Anna's hummingbirds.
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.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)
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.is the largest hummingbird that inhabits the west coast.
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.
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.
uses sound to communicate
living in landscapes dominated by human agriculture.
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.
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.
uses smells or other chemicals to communicate
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 biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly plants or parts of plants.
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.
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).
makes seasonal movements between breeding and wintering grounds
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
an animal that mainly eats nectar from flowers
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
scrub forests develop in areas that experience dry seasons.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
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).
Living on the ground.
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
living in cities and large towns, landscapes dominated by human structures and activity.
uses sight to communicate
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.