Photo by Diane Poleyquiva
(This is a recently updated and expanded version of an article I wrote and published in this newsletter in 1993.)
Unlike most of the North American hummingbirds which are known to migrate long distances, the Anna’s is considered an exception to this rule. While they travel relatively short distances as foraging and climatic conditions might dictate, they are considered a resident species – particularly in the southern areas of Arizona and California, considered ground zero within their normal range. Rather than migrating directionally as most other birds do, Anna’s can usually be found within a given area year around, moving higher in elevation in warmer weather and lower in colder weather. So in the Tucson area we notice they may be found in higher elevations in the summer but absent from those same areas other times of the year. While Southern California and Southern Arizona are the areas that Anna’s are most frequently encountered, they have been recorded breeding as far north as Humboldt Bay in Northern California and there are reports of them in breeding season as far north as Southern Alaska! Their northern range hugs the Pacific coast from northern Baja California to the Kenai Peninsula of Alaska. They are listed as accidental species in New Mexico and extreme Western Texas. They occupy a wide range of elevations and can be found from sea level to the oak ranges of the mountains. Anna’s generally prefer elevations below 5000 feet, but during hot summers in desert areas, they may move up into cooler mountain habitats. Consequently, they can be found in a wider variety of habitats than most other hummingbirds. Molting occurs in November and December.
Migratory or Resident
While many Anna’s do migrate in and out of Arizona, more and more spend all year in our desert oasis. The increase in backyard feeding over the past decades is considered a major reason this species is becoming a resident hummingbird. At backyard nectar feeders, the female Anna’s has a reputation of being more aggressive and territorial than the males.
In Tucson, they are commonly nesting before the end of January. Their breeding season can be exceptionally long – in fact, records indicate that breeding has occurred in almost all months, depending upon the location. In Southern Arizona, most breeding occurs between early winter and late spring. In the Tucson area, nest building and breeding have been recorded as early as
November and as late as September. Eggs are usually laid in December. Most babies are born in January and by late January or early February, the fledglings will leave the nest. It is believed that Anna’s will generally brood twice in a season, particularly if the first brood was predated upon or, for some other reason, was not entirely successful.
Usually, by late November or early December, female Anna’s begin nest building. They construct tiny tightly woven cup-type nests with a rim diameter of only about one and a half inches. Nests are usually covered, camouflaged really, with a generous amount of lichens, flower fragments or other pieces of vegetation attached. Nests are almost always secured to a branch or twig with incredibly strong, yet elastic, spider silk. Anchoring the nest in this manner prevents the tiny, ultra lightweight nest blowing away in a strong gust of wind. Nests are usually located in non-windy and semi-shady places.
Nests are usually located anywhere from a foot or two above ground level to around thirty feet above ground level. They are more often built next to or close to vertical surfaces: such as where a branch joins the trunk of a tree; on insulated electric wires under the crossarm of utility poles; on climbing vines; cliffs; sides of buildings; and a variety of plants – especially century plants and other forms of yucca; tree tobacco; and citrus, oak and eucalyptus trees. Folks we know in Tucson have told us they have found Anna’s nests built onto ornamental and security screen door handles, in potted plants on porches, on top of electric light bulbs and even in the pocket of a shirt left out on a clothes line. Their nests are among the largest of the hummers and very well constructed. Eggs are usually laid when the nest is only half completed. After the first egg is laid the female will split her time equally between incubating and finishing the nest. Nests are constructed of plant down held together with cobwebs and spider’s silk and often lined with fine bird feathers and more plant down. Spider silk is typically used in constructing nests. Spider silk is finer than human hair, is stronger than steel, and is very elastic. It is used in the architecture of the nest and also anchoring the nest to the branch. Finishing touches of lichens, flower parts and other plant materials camouflage the nest from predators. Females alone are responsible for the entirety of the nest building and parenting endeavors.
Eggs are incubated for 14-18 days and 18-21 days after hatching the young will take wing. Females will not use torpidity on colder nights, instead preferring to use natural body temperature to keep eggs warm until they hatch. Males, without any of the parenting duties of the females, will enter torpid states to help make it through colder nights.
Albinism and Hybrids
True albinos are rare throughout nature, including the realm of humans and hummingbirds. Leucistic birds (birds with an albino appearance) aren’t true albinos. They usually have some field marks or color that prevents them from being entirely all-white. Leucistic birds more typically have black eyes, not pink eyes usually associated with true albinos. Perhaps once a decade a lucky photographer documents a rare albino Anna’s. A small number of hybrids have resulted from Anna’s cross-breeding with other localized species. In the literature there are documented reports of Anna’s cross-breeding with Black-chinned, Calliope and Allen’s Hummingbirds. I find it interesting that all five of the earliest documented Anna’s/Allen’s hybrids turned out to be exclusively male.
Identifying Anna’s Hummingbirds is relatively easy as they are among the larger of the hummers in their home range. Adult males are easiest to recognize as their brilliant red gorget (front of the neck or throat) colors extend to the breast and encircle the neck. The adult male Anna’s is the only North American hummingbird which also has the forehead and head feathered with the same bright colors of the gorget. The adult male Costa’s shares this same distinction of full head color but the Costa’s coloration runs from amethyst to deep violet. The other major differences between the adult male Anna’s and adult male Costa’s is that the Costa’s gorget flares out on each side of the neck past the shoulders, like two swords extending backward. This is most obvious at nectar feeders when their heads are bent forward while drinking. The Anna’s has a larger, somewhat more elongated body shape than the Costa’s, which is noticeably shorter and rounder in shape. Also, the bills are somewhat different. The Anna’s bill is longer and the decurvature is downward. The Costa’s bill is shorter and quite straight, in comparison. Anna’s are also slightly longer than Costa’s or Black-chinned hummingbirds. Female Anna’s can easily be distinguished from other female species as they usually possess some small amount of color patch on the gorget. It is usually not as bright red as the male’s and quite smaller, often taking the shape of a triangle or trapezoid. Most other female species lack this coloration. Juvenile males closely resemble the females.
Behavior can also help identify the Anna’s. It is one of the two North American hummers that are known to sing. Costa’s also sings. Listen for a coarse, raspy series of squeaky notes, uttered from a perch. When displaying in either a courtship ritual or an intimidation flight, the male climbs to a height almost out of sight. He dives vertically at a tremendous speed and levels off just above the ground and in front of a calmly perching female. At the bottom of his plunge, he spreads his tail feathers and sharply cries peek! During the courtship dives, the males achieve wing beats up to 200 times per second! And, their dive speeds have been recorded at 65 mph.
The sounds most North American hummingbirds make is caused by air moving through the wing feathers. The historical record identifies their sounds as a buzzing or humming sound – hence the name. If hummingbirds are deficient in any way, it is in their limited ability to vocalize. Only a few species, chief among them the Anna’s and the Costa’s, produce anything more than simple, high pitched twitters. The syrinx (voice box) is placed far forward in the trachea (windpipe), making the bronchi unusually long. The major muscles that connect the sternum (breastbone) and the trachea in most birds to control vocalizations are completely missing in hummers, although two special intrinsic muscles exist. Feather vibrations produce the instrumental sound that the name implies.
From the historical record comes another example of Anna’s behavior. In 1910, J.H. Bowles, from Santa Barbara, California, reported an interesting hummingbird-snake incident. “I noticed a female Anna’s making repeated dives into the center of a wild rose bush. I looked for what had her attention and found a four foot snake. With the hummingbird watching from a neighboring live oak perch, I killed the snake. Its stomach contents showed it was guilty of nothing more than eating a lizard”.
“I tossed the snake on the ground near the bush and moved a short distance away to see what the hummer would do. Almost immediately the Anna’s darted down and hovered over the snake. Her head was bent down. Her caution, in contrast to normal female Anna’s hummingbird behavior, showed she may have appreciated her danger. Hovering from point to point, the hummingbird examined the snake from several angles before whirling up into the air, and away. Her behavior toward the dead snake was so different from when it was alive I believed the hummingbird was satisfied the snake was dead, therefore discounting it as a problem”.
Anna’s hummingbirds are known to eat a wide variety of foods in relation to other hummer species. In part, this is what enables them to occupy a variety of habitats and elevations. Hummingbird foods are clearly divided into two types: carbohydrates, mainly from flower nectars but also from the juices of fruits and berries; and proteins, from the minute insects and spiders they consume.
Animal protein and amino acids are derived from the wide variety of insects they consume. Insects comprise approximately 15% of their diet and are essential to their good health. Anna’s forage for insect food in several ways. They can often be seen perching on a high, exposed branch and, in the manner of flycatchers, will swoop off the perch in a circular fashion and pick off tiny insects in mid-air. Sometimes they will dart about furiously in a swarm of gnats or other small insects for several minutes at a time. In these chases, the Anna’s are extremely successful hunters, rarely missing their target. If they do miss their prey on a first attempt, they will continue to pursue that individual insect until it is caught and consumed. They also glean plant leaves (the underside of leaves are where small insects gather to rest in shade and avoid many predators) and stems for tiny insects like treehoppers, fruit flies and other types of small flies, gnats, aphids, mites, etc. Insects are also attracted to both nectar-producing and non-nectar flowers and the hummers will hunt them down wherever they can be found. Among trees that Anna’s will glean for insects up and down the bark, the most important are the oaks, eucalyptus, elms and willows. They regularly visit spider webs for silk during the breeding season and otherwise consume the spiders themselves as well as other small insects caught in their webs. Spiders seem to be their preferred food, especially small and baby spiders, which researchers estimate at between 60 and 80 per cent of their daily solid food intake. On rare occasions, the bird may find itself tangled up in the sticky webbing, which could result in their demise if they can’t free themselves before using up all their energy reserves. Several accounts have been reported of Anna’s following sapsuckers and foraging on both the sap itself (a good source of iron and protein) as well as picking a variety of other small insects that they discover get stuck in the sap.
Plant nectars comprise the majority of the Anna’s diet, usually accounting for 85% of their total food intake. Bright red tubular flowers are most sought after but other flowers in the warm ultra-violet spectrum (yellow, pink, peach, orange, red, and purple) will also be used. The list of flowers which Anna’s take nectar from would be enormously long, but there are several which seem to be preferred when available. Among the most desirable nectar sources are gooseberry, desert paintbrush, flowering eucalyptus, and tree tobacco. Tree Tobacco may be the most important of all as it has nectar-producing flowers year round, is a host plant for a wide variety of minute insects, and has branches that are very appealing for perching, roosting, and nesting purposes). Anna’s have also been known to feed on the juices of ripe fruits and berries. Oftentimes, when other types of birds visit fruit trees or orchards, those birds rarely consume an entire fruit. Usually, they will peck an opening, or perhaps the fruit split apart upon ripening, and leave the rest after taking only a small amount. The Anna’s will then come in and, if juice is present, partake in sipping some of that juice. This has been observed in citrus orchards and with other fruits like persimmon and various cactus fruits.
Grit/Minerals in the Diet
Unlike most hummingbird species, female Anna’s have been observed consuming grit – which contains additional minerals necessary in their diet. These observations were all made during nesting season when added calcium is especially important in producing thicker, stronger egg shells and rapid bone development of the young. Females have been observed hovering close to the ground picking up small grains of sand and soil. Sometimes they would plunge their bills directly into loose sand and soil. Other observations showed that the females would actually land on the ground and forage instead of the usual hovering.
In backyards, these hummers are quickly attracted to nectar feeders. It is important to use only ingredients that are found in nectar-producing flowers, not just simple sucrose (table sugar) and water. The natural nectar found in their favorite flowers is actually composed of three primary plant sugars – glucose, fructose and sucrose. To provide the ultimate nectar, the one that most closely approximates nature’s nectar, try our Wild Bird Store hummingbird nectar. Ounce for ounce, it is also the least expensive and most cost-effective nectar on the market. Go to our website for all the information on this nectar, wildbirdsonline.com. We have it available in 3 different sizes. We are aware that many folks have attracted hummers to feeders that contain solutions that are less than preferable, and certainly far removed from what nature intended for them to drink. We try to educate our customers to provide a complete and quality nectar which is inexpensive and, best of all, causes no harm.