Anna’s Hummingbird (Calypte anna)
By Stephen Buchmann, Pollinator Partnership
Watching a tiny hummingbird, wings a-blur, drinking from a sugar water feeder in your yard may not conjure up images of predatory dinosaurs like Tyrannosaurus rex, but it should. Turns out that these delicate feathered jewels we recognize as hummingbirds in North America are the closest direct living descendants of dinosaurs like T. rex. Personally, I enjoy the thought of this genetic linkage across deep time, and thinking about these marvelous aerobats as feathered diminutive dinosaurs.
The hummingbirds (family Trochilidae) are only found in the Western Hemisphere, and are most abundant in the tropical forests of Mexico, Central and South America. In the United States we have 16 breeding species in all. In my home state of Arizona 18 species have been recorded; that is more than any other state except for Texas. Few of these are year-round residents; most are just passing through, northward migrants from Mexico following blooming plants along nectar corridors. Combining the hummingbird species of the United States and Mexico, there are 48 species. Worldwide, there are at least 339 hummingbird species placed in 116 genera.
This pollinator of the month note is about a unique hummingbird familiar to millions of California, Arizona, and other southwestern residents. Anna’s hummingbird (Calypte anna) is a medium-sized bird (4 to 4.3 inches long). It is one of our most common hummingbirds. In Spanish, it is known as “colibri coronnirrojo”. The bird has a bronzed-greenish back with a pale grey chest and stomach, with green flanks. Anna’s has a long straight bill. Males are especially showy, with a brilliant pink/red throat patch (the iridescent gorget) and the color extends to the crown region of the head. It is the only hummingbird with a pink/red crown found in the United States. Females are more plain-looking but usually have a bit of red on the throat, and are perhaps a bit more gray than other female hummers. Anna’s hummingbirds can be found mostly on the west coast of North America from Alaska and southern Canada through Washington, Oregon, California to Baja and into the southwestern areas of Arizona and adjoining states. These birds tend to be permanent residents and are highly territorial at flower patches and sugar feeders. It has been estimated that the total population size of this species is around 1.5 million individuals. Their overall population seems stable and they are not considered threatened.
Anna’s are unusual among hummingbirds because the males sing during courtship. The song is thin and squeaky. Male birds perform a striking aerial display for their potential mates. Males hover in mid air and sing their raspy songs. Then, the fly very high into the air and dive-bomb a perched female. During this dive the male pulls abruptly up and its wings produce a loud popping sound. You will often hear courting males before you see them. Watching this example of animal behavior is a special treat for all naturalists and nature lovers.
The Anna’s, like all hummingbirds, are mutualists with flowering plants. Often, sitting close by or viewing with close-focusing binoculars, you can see white or yellow specks at the base of their black bills or on the crown forehead region of birds at flowers or artificial feeders. This is pollen. Certain flowers “dispense” small dabs of pollen grains onto these safe sites where the birds are unlikely to groom them off. The pollen is neatly delivered flower to flower as the birds wander and explore their territories in search of floral nectar and small insects.
Anna’s actively hunts down small flying insects as protein and lipid sources. They aim at the insects with their bills and at the last second open their mouths wide and scoop them up. This fascinating behavior has only been documented in the last few years using specialized high speed cinematography.
Hummingbirds are attracted to long tubular flowers with thin floral nectar (only about 20% total dissolved solids). Further, the flowers most visited by them are usually yellow, orange and especially red in color. Unlike bees, which are red-blind and highly stimulated by yellow, blue and UV colors, hummingbirds have visual pigments attuned to the shorter wavelengths, oranges and reds. They often will approach people wearing red caps or shirts, and red glass or plastic hummingbird feeders are super attractive and they rapidly learn their locations and revisit them again and again.
Plant families visited and pollinated by hummingbirds include the Scrophulariaceae, Grossulariaceae, and the Phyrmaceae. You may know these plants better as currant or gooseberry (Ribes spp.), monkey flower (Mimulus spp.) and Penstemons (the genera Penstemon and Keckiella spp.). Anna’s hummingbirds are frequent visitors and excellent pollinators of these four flowering plant genera.
It is relatively easy to garden for hummingbirds and care for their needs. The most important thing a gardener can do is plant multiple plants of preferred species (e.g., Salvias or Penstemons) in clumps. These are more attractive to the birds than isolated single plants. Visit your local native plant nursery and look for tubular reddish flowers that grow naturally in your region. They will require less care and expensive fertilizing and watering than the usual exotics offered by regular nurseries. A fantastic resource for finding the right hummingbird (and other pollinator) plants in your region is the BeeSmart Gardener App for Smart Phones that is freely downloadable. Plan to have blooms starting in the spring and extending as far into the summer or fall as possible. Try to include a few dead branches as sunny perches for the birds. A varied yard, that isn’t overly manicured or mowed down, will naturally provide the cover and insect feeding areas these birds and other wildlife require.
Adding one or two hummingbird sugar water feeders is also a good idea to help maintain the birds and increase your viewing pleasure. Prepare the table sugar to water mixture in the ratio of 1 part sugar to 4 parts water. The floral nectar within tubular flowers that hummingbirds prefer is naturally dilute at about 20% sugar. Take care to replenish the sugar solution every few days and keep the feeders clean.
Since hummingbirds are ideal to watch either unaided or with binoculars, you can have fun as a citizen scientist! Make your own observations on the kind of birds you see at flowers or feeders and what times of the day they’re most active. Join an observing organization like Operation Ruby Throat and add your observations to a growing body of knowledge on these beautiful pollinators. Keeping a nature journal to enjoy these birds even more - this can challenging and fun activity for young and old.
- Hassler, L. 2001. Hummingbirds of the American West. Rio Nuevo Publishers, Tucson, AZ. 76 pp.
- Williamson, S. L. 2001. Hummingbirds of North America. A Peterson Field Guide. Houghton Mifflin Company, New York, 263 pp.