Cover photo: © jacksnipe1990, 2017, Flickr Photo Album, some rights reserved.

Anna’s hummingbirds are permanent residents in the Bay Area.

While some species of hummingbird migrate during the winter, the Anna’s hummingbird stays in the Bay Area year-round.

Their range has greatly expanded beyond its initial restriction to California and Baja California. Today, Anna’s hummingbirds can be found in parts of the southwestern United States, as well as up in British Columbia, Canada. Their expansion is thought to be related to their adaptability to feeding on exotic flowers and their use of artificial food sources (hummingbird feeders).

Anna’s hummingbirds are the most common hummingbirds on the west coast.

They can be found in a variety of habitats, ranging from urban gardens to open oak woodlands. Individuals can be located easily by listening for their buzzy song, which is often sung from atop a perch.

Anna’s hummingbirds eat nectar and insects.

Anna’s hummingbirds feed of nectar from native and non-native plant species, as well as artificial nectar provided at hummingbird feeders. It’s estimated that 90% of a hummingbird’s diet is composed of nectar, whereas the remaining 10% is composed of small insects.

Anna’s hummingbirds are a bright and feisty visitor at my own hummingbird feeders. They can be quite territorial, as exemplified by some individuals perching near the feeders and chasing away any unwelcome visitors that wander over in search of food.

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Source: © Mick Thompson, 2017, Flickr Photo Album, some rights reserved.

Anna’s hummingbird males generate a non-vocal “squeak” during their breeding displays.

During the breeding season, male Anna’s hummingbirds display for females. During their display, males sing energetically, then rise up to 130 feet into the air. They follow this flight with a sudden and quick dive. As they dive, a “squeak”-like sound is produced by air moving through modified outer tail feathers.

Females are responsible for all nesting responsibilities.

Anna’s hummingbirds have a breeding system in which females are solely responsible for parental care. Female Anna’s hummingbirds construct nests of soft plant fiber and spiderwebs that are 1.5 inches in diameter and 1 inch high. She lays 2 eggs, which take 16 days to hatch. Once hatched, the female will feed and care for the young until they are old enough to fly out of the nest at 23 days old.

Cool facts about Anna’s hummingbirds:

  • In the Bay Area, an Anna’s hummingbird nest once delayed construction at the Richmond-San Rafael bridge. The nest, protected under the Migratory Bird Treaty Act, was discovered in a grove of trees designated to be cut down for the expansion. The crew halted removing the trees until after the nest and birds were gone.
  • Anna’s hummingbirds are capable of torpor. When temperatures drop outside at night, Anna’s hummingbirds will also drop their own body temperatures. They simultaneously slow their heart rates and breathing to enter a hibernation-like state. Once temperatures rise again, they resume normal bodily functions.
  • All hummingbirds are only found in North and South America.

Resources to learn more:

Posted by Taylor Crisologo

Taylor studied biology at Cornell University, where she worked with the Cornell Lab of Ornithology on projects ranging from breeding herring gulls off the coast of Maine to dancing lyrebirds in Australia’s Blue Mountains. When she’s not researching great places to experience Bay Area nature, you can find her birding or reading a book at home with her fiancé Dan and their two cats (Max and Penelope).

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