Anna’s Hummingbird
by Dave Zittin
One reason to love Anna’s Hummingbirds is that they are attracted to bright colors, which they often investigate as potential food sources. I have had hummingbirds hover near my shirt pockets that contained bright-colored pens. And, when I was a university student living in Northern California, I kept a red-colored hummingbird feeder outside our living room window. As an experiment, I kept the window open and moved it into the living room short distances every day or two. After several days, our resident Anna’s Hummingbird flew through the window opening, across the living room, and into the dining area, where the feeder was hanging. I guess you can say we all ate together.
Male Anna's Hummingbird with some of its gorget feathers showing iridescence. Photo by John Richardson.
Hummingbirds allow people to get close. If you stand still next to a feeder, Anna’s will feed inches from you. Hummingbirds feed on nectar and insects. Insects provide protein, and nectar gives them the sugar energy they need for their high metabolic rate. Insects are an essential source of protein for their growing young.
Anna’s and other hummingbird species take advantage of sap wells made by sapsuckers. In addition to sap, these wells attract insects that both the sapsucker and hummingbirds consume. Interestingly, some hummingbird species follow sapsuckers during migration in order to use sap wells as a food source. Studies show that some hummingbirds are able to migrate into northern areas earlier than they would otherwise be able to because sap wells provide energy before their preferred plants bloom. Anna’s Hummingbirds are significant pollinators of many wild plants, including sticky monkey flower, gooseberry, currant, and the California fuchsia.
Hummingbirds occur only in the New World. They fascinated early European explorers, who thought they were insects or the result of a bird-insect hybridization. Later, hummingbird feathers and their desiccated bodies became fashionable in Europe until the early 1900s when the Migratory Bird Act ended the taking of wild birds for such purposes.
Female Anna's Hummingbird showing red spots on the neck. Photo by Brooke Miller.
Anna’s Hummingbird belongs to the large family Trochilidae (trochil=a small bird), which contains well over 300 species. Hummingbirds and swifts are members of the order Apodiformes, or “footless.” They have very small, skin-covered feet that are used for perching only; they move from place to place by flight. Anna’s Hummingbird is a member of the genus Calypte, which translates to approximately “veil” or “head-dress.” There are two species in the genus, Anna’s and Costa’s Hummingbirds.
In 1829, natural historian and surgeon René Lesson named Rivoli’s Hummingbird in honor of the second Duke of Rivoli (Italy), an avid amateur ornithologist. Dr. Lesson named Anna’s Hummingbird after the duke’s wife, Duchess Anna.
Attracting Anna’s Hummingbirds to Backyards
Attracting Anna’s Hummingbirds to a backyard is easy; purchase a hummingbird feeder. Mix a sugar-water solution according to the directions given in the “using feeders” link below. Be sure to clean the feeder regularly as the sugar solution promotes mold. I have a circular feeder with a red top and five holes. I use a stiff bottle brush and soapy water to clean the sugar trough and the holes in the top of the feeder prior to each refill. If you want to start a feeder, be sure to first read the feeding reference.
Female Anna's Hummingbird. Note the red spots on her throat. Also, note that there are no reddish-rust colors on her flanks. Photo by Brooke Miller.
Description
The color patterns of the two sexes are different (called sexual dimorphism). Anna’s female is relatively drab, which gives her a camouflage advantage when incubating eggs. The male is bright green with a brilliant pink-reddish gorget, the colorful patch found on the throats of hummingbirds. The gorget of the male Anna’s is unusual because it extends up and across the forehead. The brilliant iridescence of hummingbirds is due to refracted light coming from minute bubble structures located in their feathers, not from pigments. The gorget appears dark-colored until the angle of sunlight on the feathers and the angle of your eye to the feather surface interact to produce a visual gem.
Male Anna’s Hummingbird not showing iridescence, the light-source and view angles are important. Photo by David Zittin.
Male Anna’s Hummingbird showing iridescence. Photo by Dave Zittin.
Anna’s breeding season starts in November when rain promotes currant and gooseberries to flower and insects become abundant. The breeding display of the male is unique to this species. His courtship dive starts higher than any other hummingbird species, at about 115 feet above the ground. From there, he does a near-vertical dive, reaching descent rates of 90 feet/sec. He then turns up near his potential mate, yielding a “J”-shaped dive profile. He experiences about 8.5 Gs as he turns up at the bottom of the “J”. Most people subjected to 6 Gs for more than a few seconds will pass out. At the bottom of the “J”, air movements over his tail create a loud chirp or squeak sound. There is no pairing, the male courts and copulates, nothing more. The female does the nest building and rearing of the young.
Distribution
In the early part of the 19th century, Anna’s Hummingbird occurred across southwestern California and south into northwestern Baja California. Since the middle of the 20th century, human plantings have encouraged this species to spread northward. Eucalyptus, various ornamental flowers, and some fruit trees contributed to the spread of Anna’s. Of course, hummingbird feeders also contributed to their northward spread. Today Anna’s is found in Northern Baja California, west into Southern Arizona, and north along the coast into Southern British Columbia.
Anna’s Hummingbird can greatly slow its metabolism during cold periods to conserve energy. This metabolic slow-down is called torpor. Its average normal body temperature is 107 ℉ and its resting heartbeat rate is 400 beats/minute, but in torpor, its temperature falls to around 48 ℉ and its heartbeat rate drops to around 40 beats/minute. Being able to shift metabolic gears also aided in its northward range expansion. Anna’s Hummingbird is present in Santa Clara County throughout the year.
Similar Species
Three other hummingbird species occur in Santa Clara County, but not for the entire year. These species are the Rufous, the Allen's, and the Black-chinned Hummingbirds. The Calliope Hummingbird appears in the county infrequently. Male Anna’s are easy to identify. It’s the only hummingbird in the United States with a reddish-pink gorget that extends over its forehead, giving it an iridescent reddish-pink crown. Identifying the female is more problematic. Female Anna’s can be identified if you see red spotting on the throat. However, the red spotting is not always obvious. Female Anna’s Hummingbirds never have rufous or cinnamon coloring on their flanks, as do Allen’s and Rufous Hummingbird females. Without red spotting on the neck, the female Anna’s is similar to the female Black-Chinned Hummingbird and can be difficult to tell apart for the beginning birder.
Explore
General Information on Hummingbirds
Trochilidae by Animal Diversity Web, University of Michigan
Hummingbirds and Sapsuckers
Why a Sapsucker may be a Hummingbird’s Best Friend from The Bird Guide
Color in Birds
Iridescence Revealed in the Feathers of an Anna’s Hummingbird from All About Birds
How Birds Make Colorful Feathers from All About Birds
The Basics of Iridescence in Hummingbirds from Sibley Guides
Using Feeders
Feeding Hummingbirds by All About Birds
More Backyard Bird Information
View more common Santa Clara County Backyard Birds
Visit our Backyard Birding page
Read our Notes and Tips from a Backyard Birder series
Tell us what you’re seeing in your yard! Send your notes, photos, and sound clips to backyardbirds@scvas.org. We’ll feature your submittals on our website.
Banner Photo: Anna’s Hummingbird by Tom Grey