Although this hummingbird generally nests only in California, it has expanded its breeding range in recent years north to Vancouver, British Colombia, and east to southern Arizona. This expansion has been aided by the introduction of exotic flowering plants, especially Eucalyptus, red-hot-poker, and tree tobacco, and by the presence of hummingbird feeders. The Anna's Hummingbird is the only hummingbird with a winter range primarily in the United States. Its mostly green body and iridescent red throat feathers make identifying it easy; the male also has a red head.

Anna's Hummingbirds are highly territorial and often perch on the tip of a high branch where they constantly turn their head searching for intruders. The males will often sing on these perches - this is the only hummer in California to have a true song. Both males and females make a sound like a baby chick as they move from flower to flower to drink nectar.

As with other hummingbird species, male and female Anna's Hummingbirds associate only long enough to mate. Females are entirely responsible for building the nest and caring for the young. During the breeding season, males and females occupy separate habitats. Males establish feeding territories on slopes in open chaparral while females build their nests in shaded woodlands, often in live oak, eucalyptus, or gardens.

The breeding season begins in December and lasts until May or June. In Sonoma County, mothers have been seen tending young as early as mid-February! Males begin defending their territories before females, choosing areas associated with flowering plants containing abundant nectar. Females arrive a few weeks later and establish separate territories; there they build camouflaged nests made from plant down and spider webs. When the nest is partially built, the male performs his courtship display. First, he hovers before the female, then rises high, sometimes pausing to sing a thin, squeaky warble of a song before diving toward the ground, making a loud popping noise at the bottom of the dive. Incubation of the eggs takes about two weeks before the naked and blind nestlings hatch. After three weeks, the young may leave the nest, although they remain dependent upon the mother for food for a few days. Juveniles rapidly develop territorial behavior, sometimes establishing their own feeding territories shortly after leaving the nests.

The adults' tiny body, weighing only 3.4 to 5.8 grams (a paperclip weighs about one gram), along with its rapid wing beat, 30 - 50 beats per second, makes it necessary for them to eat constantly. A favorite native food source is the nectar of red gooseberry, an abundant plant that flowers early in spring, when the Anna's Hummingbird begins nesting. It is thought that the gooseberry and the hummingbird have evolved together, resulting in Anna's Hummingbirds' unusually early breeding season. Anna's also eats more insects than any other North American hummingbird, catching small flying insects in midair, or by gleaning among the leaves and twigs of trees.
Text by Amy Kelsey.

Identification Tips:

Length: 3.5 inches
Long, straight, thin bill
Medium-sized hummingbird
Green back
Gray underparts with greenish flanks

Adult male:
Rosy-red iridescent crown and gorget
Entirely dark tail

Female/Immature:
Green crown
Gray chin and throat with variable amounts of thin
dark streaking or rosy red spots depending on age
and sex
Dark tail with white tips on outer tail feathers

Similar species:
Males unmistakable when red crown is seen but beware
of poor lighting conditions. Females and immatures are
fairly large and gray breasted, and often show the
distinctive rosy-red gorget color on the throat. Costa's
and the two Archilochus hummingbirds are the most
likely identification contenders, but are smaller with
whiter breasts and different call notes.

Length and wingspan from: Robbins, C.S., Bruun, B.,
Zim, H.S., (1966). Birds of North America. New York:
Western Publishing Company, Inc.

ID Tips by U.S.G.S.

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