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.
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.
- Habitat Regions
- temperate
- terrestrial
- Terrestrial Biomes
- forest
- scrub forest
- Other Habitat Features
- urban
- suburban
- agricultural
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.
- Other Physical Features
- endothermic
- heterothermic
- bilateral symmetry
- Sexual Dimorphism
- sexes colored or patterned differently
- male more colorful
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.
- 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.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- oviparous
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
-
provisioning
-
pre-weaning/fledging
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-independence
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
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.
- Key Behaviors
- flies
- diurnal
- motile
- migratory
- solitary
- territorial
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.
- Primary Diet
- herbivore
- 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.
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.
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.
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.
Additional Links
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.
- 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.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- 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.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- scrub forest
-
scrub forests develop in areas that experience dry seasons.
- urban
-
living in cities and large towns, landscapes dominated by human structures and activity.
- suburban
-
living in residential areas on the outskirts of large cities or towns.
- agricultural
-
living in landscapes dominated by human agriculture.
- 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.
- 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.
- 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.
- polygynandrous
-
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- 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).
- 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
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- 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.
- diurnal
-
- active during the day, 2. lasting for one day.
- motile
-
having the capacity to move from one place to another.
- migratory
-
makes seasonal movements between breeding and wintering grounds
- solitary
-
lives alone
- 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
- herbivore
-
An animal that eats mainly plants or parts of plants.
- nectarivore
-
an animal that mainly eats nectar from flowers
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals 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. 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 .