Bent Life History of the Anna's Hummingbird
Published by the Smithsonian Institution between the 1920s and the 1950s, the Bent life history series of monographs provide an often colorful description of the birds of North America. Arthur Cleveland Bent was the lead author for the series. The Bent series is a great resource and often includes quotes from early American Ornithologists, including Audubon, Townsend, Wilson, Sutton and many others.
Bent Life History for the Anna's Hummingbird - the common name and sub-species reflect the nomenclature in use at the time the description was written.
CALYPTE ANNA (Lesson)
CONTRIBUTED by Robert S. Woods
In two respects Anna's hummingbird occupies a unique place among our hummingbirds. It is the only species the greater part of whose general range is included within a single State of the Union, and the only one that winters mainly within the United States. It is also the species most familiar to residents of California, since its territory includes all the more populous districts of the State, where it is a constant and by no means shy visitor to city parks and gardens. Anna's hummingbird seems to be in some degree nomadic in its habits, and it probably shifts slightly southward during the colder months, but it performs no true migration, thereby differing from all our other species except that portion or race of Allen's hummingbird resident on the Channel Islands of southern California.
Courtship: In April, in the blooming orange groves of southern California, at least five of the six species of hummingbirds regularly occurring in that region may sometimes be seen together, in considerable numbers and feverish activity. No small part of that activity consists in the practicing of highly specialized forms of courtship flight. While the males of all California hummingbirds can easily be recognized when clearly seen, identification is more difficult when the bird persists in manifesting itself as a vague streak rather than a definite object. Under these circumstances a knowledge of the specific distinctions in "nuptial flight," and particularly of the peculiar and entirely characteristic utterances accompanying such flight, is often of great assistance in determining species.
The most elaborate of these nuptial flights is that of Anna's hummingbird, in which the bird mounts upward until almost lost to sight then shoots vertically downward at tremendous speed, finally altering his course to describe an arc of a vertical circle, which carries him as closely as possible past the object of his attention as she sits quietly in some bush or tree. At the lowest point of the circuit he gives utterance to a loud, explosive chirp, which so nearly resembles the "bark" of a California ground squirrel (Citellus beeckeyi) that one who is familiar with that sound may easily be deceived. From this point he continues along the arc until he arrives at a point directly above his mate, where he hovers for a few seconds with body horizontal and bill directed downward, rendering his squeaky "song." Then, without change of attitude, he begins to rise rapidly and vertically, repeating the entire maneuver until he tires or the other bird departs, with himself in hot pursuit.
Presumably this practice originated strictly as a courtship display, but it now has a much broader application, frequently being directed at other species or at birds of wholly different kinds. Young males begin performing the flight as early as September of their first year, and it is continued through at least the greater part of the year. Anna's hummingbird is not addicted to the shuttling flight so much used by those species in which the wings of the males are modified in such a way as to produce a metallic rattling sound. The actual mating, which is not often witnessed, has been described by Leroy W. Arnold (1930): "When first observed, the birds were playfully chasing each other about and suddenly swooped down to within about eighteen inches of the ground where the leading bird, which proved to be the female, stopped and faced about. The male approached and the mating was consummated in the air, the birds breast to breast and with the male somewhat under the female. The male then settled down to the ground for a few moments, fanning out his tail and pointing his beak upward, while the female flew to a nearby perch. After a short rest, the male rose and flow after the female who returned to her former position and mating again took place as before."
Nesting: With reference to the nesting habits of hummingbirds, few distinctions can be drawn between the various species even under quite different ecological conditions, except in the matters of season, locale, type of site, and nest materials. The nesting of Rieffer's hummingbird (Amarilia tracatl tzacrzti) in Central America has been carefully observed by Alexander F. Skutch (1931), and the agreement in procedure between this species of the humid Tropics and those of the semiarid Temperate Zone is most striking. The principal specific variations in this connection among North American hummingbirds concern the selection of materials for the nest, but there m also considerable individual latitude that tends to bridge the gaps.
Although Anna's hummingbird is generally distributed west of the Sierra Nevada and the Colorado Desert, it is rather definitely classified as a breeder in the Upper Sonoran Zone and is less partial to arid localities than is Costa's hummingbird. The nesting season begins before the arrival of any of the migrants, sets of eggs having been found by various persons as early as December. The nesting probably continues normally through late winter and spring and sporadically throughout summer, with some evidence of its extending even into the fall. With the breeding season so greatly prolonged. it is of course difficult to determine exactly how many broods are raised each year, but it may be inferred that two is the usual number, as in the cases of the black-chinned and Allen's hummingbirds. During one season throughout which I was able to follow the activities of one pair separately, by the aid of artificial feeding, the movements of the female indicated: though the nest was not found: that the first incubation period began late in January, the second just two months later. Incidentally, it is hard to explain satisfactorily why these species, which quite certainly raise two broods yearly, do not gain in numbers relatively to the Costa's, rufous, and calliope hummingbirds, which usually do not remain on their breeding grounds long enough to permit more than one.
Nests of Anna's hummingbirds have been described or photographed on almost every kind of site to which it would be possible to attach the structure, except on the ground or any extensive horizontal surface. It is usually, without doubt, birds of this species that now and then achieve newspaper publicity by nesting in some unexpected spot in the business district of Los Angeles. The distance from the ground at which the nests are placed is also extremely variable. Of 52 nests found by W. Lee Chambers (1903) between January 1 and February 18, 1903. the heights ranged from 17 inches to 30 feet. James B. Dixon, of Escondido, Calif., writes (MS.) concerning nests and their sites "The female seems to select the nesting site and so far as I have ever observed did all of the nest building. The nest location may be in a wide variety of locations, as I have seen nests in the following locations: On insulated electric-light wires under the crossarm of a service pole 30 feet from the ground; on a climbing vine on a granite cliff face within a few feet of an occupied nest of the golden eagle; in citrus trees, both oranges and lemons; in brush far removed from any wooded areas; and in dense oak groves in narrow wooded canyons. The last-mentioned place is by far the most favored as to nest location and I should say was typical of this area. The nests are large and well made and are usually devoid of camouflage when first built but are decorated with lichens during the incubation period and by the time the young are hatched are very beautiful structures and in my estimation are the most beautiful of all the hummingbird nests. The nests are made of plant down put together with cobwebs and are often lined with fine bird feathers and plant down. Often eggs are laid in the nest when it is a mere platform and the remaining part of the nest is built up around the eggs and the finishing touches of lichens and plant seed put on last.
Two eggs are usually laid, although I have seen nests with one and three eggs, which I feel sure were sets. The female is usually very tame after brooding a short time and is very curious if disturbed and will fly right into your face to look you over and try to scare you away from the nest. I have never seen the male bird feed the young or help build the nests. Anna's hummingbird does not colonize like some of the others and seems to prefer an area to itself."
W. Leon Dawson (1923) states that "nests of the Anna Hummer vary in construction perhaps more widely than those of any other local species. Some are massive and as heavily adorned with lichens as those of the eastern Ruby-throat." According to all available data, however, they can probably be regarded as essentially similar to those of Costa's hummingbird except for their slightly larger size; fibers and stemmy materials usually being used in the walls, and ornamentation on the exterior, while feathers are frequent in the lining. An interesting account of the nesting activities has been given by A. W. Anthony (1897)
Sometime about April 1, an Anna's Hummingbird began her nest in a cypress In front of my residence in San Diego. I could not be sure as to the exact date of beginning, hut on the 6th, when I first noticed the bird at work, there was nothing but a little platform the size of a silver twenty-five cent piece, fastened to the upper side of a twig which nearly overhung the front walk, and was but just high enough to escape being struck by anyone passing below.
From an upper window I could look down upon the growth of the downy cup, and watch the diminutive builder from a distance of but a few feet, as she brought almost imperceptible quantities of cotton and tucked them into the sides and rim of the prospective nest. In working the material into the structure she always used her body as a form around which to build, tucking the cottony substance Into the side and pushing it with her breast, frequently turning about to see if It were the right size all around.
On April 12, when the nest was apparently but half finished, and little better than a platform with a raised rim, I was surprised to see an egg, which the mother carefully guarded. as she buzzed about, still bringing nesting material.
The following morning the second egg was added, and on one or two occasions the male made his appearance, and tried, seemingly, to coax the female to leave the nest, even making several attempts to push her from the eggs when other means failed. He soon became discouraged, however, and departed for parts' unknown, leaving his demure little spouse to care for the eggs and complete the half finished nest.
For several days incubation progressed just about two minutes at a time. The Hummer, after arriving with material and building it into the slowly rising rim, would Incubate for two minutes, seldom more than a few seconds more or less, before leaving for another consignment.
Her periods of absence were of almost exactly the same duration. It was not until Incubation was more than half complete that the nest was finally finished, but unadorned by the usual bits of lichen. These were added from day to day until May 1, when the first egg hatched, either eighteen or nineteen days after incubation began. Owing to the unsettled actions of the bird on the 12th and 13th of April I could not satisfy myself as to when incubation really began.
The second egg never hatched, and after the nest was abandoned the broken shell was found buried in the bottom of the nest.
Eggs: [Author's Note: The usual two eggs of Anna's hummingbird are indistinguishable from the eggs of other hummingbirds of similar size. The measurements of 50 eggs average 13.31 by 8.65 millimeters; the eggs showing the four extremes measure 14.3 by 9.0, 12.7 by 9.4, and 11.3 by 7.7 millimeters.]
Young: It will be noted from Mr. Anthony's account that the incubation period is considerably longer than that of most common passerine birds, despite the smaller size of the eggs. This is confirmed in the following description by 41. H. Bowles (1910) of the nesting of an Anna's hummingbird at Santa Barbara:
The first egg was laid January 3, but during the following night a heavy frost left ice more than a quarter of an inch in thickness on the puddles.
I think the icy weather must have been too severe for the first egg, for, whatever the cause, only one egg hatched. This took place on January 22, showing the period of incubation to be just seventeen days. It may be Interesting to note here that I have found thirteen days to he the period of Incubation for eggs of the Black-chinned Hummer (Arcltilockus alemandri). This great difference I think may be attributed in part to the consistency of the albumen, which in eggs of C. anna is thick and almost gummy, while in A. alezandri It is thin as in eggs of other small birds.
In spite of the very cold, rainy weather my young hummer grew very rapidly; hut it was not until he was thirteen days old that his eyes opened. * * *
On February 13, when he was just three weeks old, the young bird left the nest.
I believe, however, that the difference in incubating time between Anna's hummingbird and other species cannot be so great as assumed by Mr. Bowles, as I have found the period for both black-chinned and Costa's to be about 16 days, while, on the other hand, Donald R. Dickey (1915) gives an even shorter time for Anna's hummingbird, as observed in the Ojai Valley of Ventura County:
Finally, on the fourteenth day of incubation: a long period for so small a bird: the young hatched into black, grubby caterpillars, with smoky fuzz in two lines down the back, and squat, yellowish mouths that gave no hint of the future awl-like hills. Now the mother's care was redoubled, and on the fifth day their eyes opened. Two days later respectable pin feathers transformed them from loathsome black worms into tiny porcupines.
Now we saw more and more often the grewsome-seeming spectacle of their feeding. The female's foraged burden of small Insect life, culled from the flowers' corollas, and doubtless nectar-sweetened, is transferred to the young by regurgitation, and to avoid waste the mother's needle bill is driven to its hilt down the hungry youngster's throat. It suggests, as someone has said, a major surgical operation," but the young so obviously enjoy and thrive upon it that we outsiders slowly lost our fear for them. At last the feathers broke their sheaths and the wee mites took on the semblance of real hummers. And then one night the worst happened: a prowling cat found the nest and exacted nature's price of death.
The disagreement in the figures of Bowles and Dickey as to the age at which the eyes are opened is probably due to the fact that the eyes are habitually kept closed for a good while after they are capable of being opened. Despite the great number of nests described or recorded, there seem to be few published figures on the length of time the young Anna's hummingbird remains in the nest. The single occupant of the nest watched by Mr. Anthony left after 18 days, undoubtedly a shorter than average time, since the period of three weeks recorded by Mr. Bowles corresponds very closely with my determinations for Costa's and the black-chinned, which range from 20 to 28 days for each species. This period in the case of the hummingbirds is more uniform than it is with most species of passerine birds and averages at least 50 percent longer.
Plumages: The molting of the body plumage, as indicated by a slightly unkempt appearance, seems to take place in July and August. The luminous feathers of the crown and gorget are not replaced at that time, however, but begin to be shed in October, the ruff being completely lost and the throat and head becoming decidedly ragged, the former showing streaks of gray. The entire process to the completion of the new gorget requires perhaps a month. During this time the remainder of the plumage shows no sign of molting. The practice of the "nuptial flight," in so far as I have observed, seems to he discontinued during this period.
The outline of the gorget becomes visible on the throat of the young male soon after it has left the nest. The area gradually becomes sooty black, with glints of red, and slowly grows redder, the throat feathers lengthening into a ruff. Even in fall, however, when this first gorget is apparently complete, it still is lacking something in brilliancy and form; but it is almost immediately shed, to be replaced by the full perfection of the adult.
In the male Anna's and Costa's hummingbirds, alone among the species occurring in the United States, the crown is like the throat in color, but the two differ from each other not only in the color of the gorget but in its shape. As viewed from the front, that of Anna's is deeper and its lower border forms nearly a straight line, while the lower outline of the Costa's gorget is decidedly concave and its ruff is narrower and more prolonged. In both, the area of the crown is separated from that of the throat by a light streak running backward and downward from the eye, but in the Anna's only a very narrow gray line divides the luminous area behind the eye from that of the crown.
Among hummingbirds, and especially in the present species, individual variations seem more pronounced than among most birds. The color of the back ranges from slightly bluish metallic green to decidedly bronzy green in different individuals; the rose-red of the crown and gorget changes to purple as a secondary color in some instances, while in others gold and greenish lights are frequently seen. Ridgway (1892) refers to this as "perhaps the most beautiful of North American Humming Birds" and quotes Gould's Monograph of the roohilidae as follows:
When studying the diversified forms and coloring of the Trochilidae, I have frequently been struck with the fact that those districts or countries having a metalliferous character are tenanted by species of hummingbirds which are more than ordinarily brilliant and glittering. This is especially the case with the species inhabiting Mexico and California: in illustratien of this assertion, I may cite the three California species, Selosphorus rufus, C. cesfee, and the present bird, C. anna, all of which are unequaled for the rich metallic brilliancy of certain parts of their plumage, by any other members of the family. The two latter, C. cesfee and C. anna, have not only the throat, hut the entire head as glitteringly resplendent as if they had been dipped in molten metal.
Food: The food of the hummingbird is divided quite definitely into two classes: Carbohydrates, consisting of the nectar of flowers and more rarely of fruit juices and the sap of trees; and proteins, as furnished by the minute insects and spiders obtained either in conjunction with the other food or as the product of separate hunting activities. In late afternoon or on a cloudy day a hummingbird may frequently be seen perched upon some exposed twig or wire, from which it sallies forth at intervals to engage in strange aerial evolutions that might well mystify a stranger. since the flying insects it pursues are too small to be discerned at any distance. A specific instance of this sort is thus described by Frank F. Gander (1927) "On the morning of Thanksgiving Day, November 25, 1926, in Balboa Park, San Diego, California, I watched three male Anna Hummingbirds (Calypte anna) catching insects on the wing. A rain the night before had cleared the air and I could easily see the sun glistening on the gossamer wings of a host of tiny midges flying all about me in the air. The male hummers would hang on rapidly vibrating wings for a second and then dart suddenly a short distance and one of the glistening insects would disappear. This was repeated time and time again, and the birds seldom missed; on the rare occasions when they did miss they relentlessly pursued their chosen prey until it was captured."
Many observers have mentioned the hummingbirds' habit of searching the trunks and branches of trees for animal food and of extracting from spiders' webs small entangled insects or even the proprietors themselves. In their account of Anna's hummingbird in the Yosemite Valley, Grinnell and Storer (1924) have described some of its lesser known feeding habits:
During November and December of 1914 we saw individuals almost daily at El Portal. At this time of the year there were no flowers of any sort to be found In the vicinity, but the Anna Hummingbirds seemed to find enough good forage on the foliage of the golden oaks, about which they were seen almost exclusively. The minute Insects which live on the leaves of the golden oak probably afforded sufficient forage of one sort, but the hummingbirds had another source of food supply.
It was noted that one or more Anna hummingbirds were to be found regularly about a certain golden oak, but the reason for their attraction to this particular tree was not discerned for several days. Then, on December 11, one of these birds was seen hovering before, and drinking from, some punctures made by a Red-breasted Sapsucker in the bark of the oak tree. The hummer visited puncture after puncture just as it would the individual blossoms in a spike of flowers, and evidently partook of both the sap and the smaller of the insects which bad been attracted by the sap.
It is rather contrary to the traditional conception of hummingbirds that they should deliberately frequent the higher altitudes devoid of flowers, but there are undoubtedly times, following especially severe frosts, when members of this species in many parts of California must be compelled to obtain their living in other than the usual way. Mr. Dawson (1923) also mentions the use of sap: "Anna's Hummer is fond of the sap of our common willows (Salix laevigata and S. lasiolepis). It will also follow the Red-breasted Sapsucker (Spayrapwus ruber) into the orchards and glean eagerly from its deserted borings. A catalogue of Anna's favorite flowers would be nearly equivalent to a botany of southern California. But if one had to choose the favorite it would probably be Ribes speciosum, our handsome red flowering gooseberry, for it is upon the abundance of this flower that Anna relies for her early nesting."
Naturalists in the eastern and northern parts of the country have found that hummingbirds are more attracted to red flowers than to those of any other color. The early-flowering gooseherry above mentioned and the paintbrush growing along a creek, which M. P. Skinner, in his notes, tells of seeing are Anna's hummingbird visit to the exclusion of other flowers, are both red: but in all these cases the flowers are probably seen against a green background, and since red is the complementary color of green, the greater visibility of that color may be more. of a factor than any preference which the birds might feel. At any rate, there seems to be no such favoritism in the more arid parts of the Southwest, where the backgrounds are often grayish or tawny. Bits of red and blue cloth seemed to attract equal attention, though green was ignored.
Like most young animals, immature hummingbirds are filled with curiosity and are quick to investigate any brightly colored object; a bunch of carrots will attract them as readily as a flower. Through this process of trial they presently learn to discriminate among the flowers and often to choose those of inconspicuous appearance over the more brilliant kinds. As experience thus supplants curiosity, they cease to show much interest in unfamiliar brightly colored objects, unless it may be in times of food shortage, or when invading new territory where exploration must be carried on to locate its floral resources. Among familiar surroundings, memory for location undoubtedly guides the hummingbird to a large degree in its feeding.
As a general rule, hummingbirds prefer flowers of tubular form and are comparatively indifferent to composites and double flowers, such as roses. Within certain limits, size seems to be of little moment. One of the most valuable plants to Anna's hummingbird, especially, is a naturalized introduction from South America, the tree tobacco (2vicotiana guinea). This tall, sparse-foliaged, drought-resistant shrub bears a profusion of narrowly tubular blossoms practically throughout the year. Somewhat sensitive to cold, it is found only in the warmer parts of California. As an example of the hummingbirds' frequent disregard of bright coloring, they will probe the greenish-yellow newly opened flowers of this plant in preference to the purer yellow mature blossoms, which evidently contain less nectar. The greatest concentration of hummingbirds is seen about the tall, treelike flower stalks that culminate the life cycle of the common "century plant~~ (Agate americana), abundantly grown in California. The numerous greenish-yellow blossoms are dull-colored, but evidently they offer a rich store of nectar. Various species of eucalyptus, some of which bloom in winter, also attract large numbers of hummingbirds. The State of California must now be capable of supporting a much larger population of these birds than would have been possible under primitive conditions.
At times when their natural food is scarce, hummingbirds will gladly avail themselves of offerings of saturated sugar solution, which seems to be preferred to commercial honey. When flowers are plentiful and hummingbirds not too numerous they pay less attention to the artificial food than do the orioles and house finches, which are equally fond of sweets and not so well fitted to extract them from the flowers. It is during the latter half of the year that the hummingbirds will make most frequent use of sugar syrup in order to compensate for the comparative scarcity of flowers, though when the habit is once formed it may be continued even through spring. Visits are made at intervals during the day, perhaps only half-hourly when the temperature is high, but with increasing frequency toward evening, the height of this activity occurring between sunset and ten minutes after, when feeding ceases for the day. The use of clear glass vials affords an opportunity to observe the hummingbird's manner of drinking. When the liquid is out of reach of the bill, it is lapped up by rapid movements of the tongue, which can be extended an additional distance equal to the length of the bill. Should the vessel be filled nearly to the top, the syrup is either sipped with the end of the bill submerged or lapped with the tip of the bill held just at the surface and the tongue protruded only slightly. An Anna's hummingbird ordinarily consumes about two teaspoonfuls of saturated solution daily, only a few drops being taken at a time.
Various means may be used for the artificial feeding of the hummingbirds, ranging from small vials tied to the branches of trees to large and elaborate self-feeding devices, with provisions for discouraging the visits of ants, bees, and larger birds. Syrup in ordinary small brown bottles is often discovered by the birds without any kind of lure, but in more complex arrangements it is usually necessary to first guide them by inserting a flower in the opening. A change in the design of the container will cause much confusion and uncertainty for a time. Of other liquids than sugar solution, maple syrup and strained honey are acceptable, though the latter sometimes seemed to cause inconvenience because of its viscosity. Milk was not taken, and preserved fruit juices. though heavy with sugar, were apparently not palatable.
Naturally the proportion of liquid food in the ordinary diet of the hummingbird cannot. be determined by an examination of stomachs, but Junius Henderson (1927) lists the identified contents of a large number of stomachs, as reported by Beal and McAtee in Farmers' Bulletin 506 (1912), as follows: Anna hummingbird (Calypte anna), 111 stomachs: vegetahle matter, only a trace of fruit pulp Diptera (gnats a.nd small flies, largely neutral), 45.23 percent; Hymenoptera, mostly useful, 35.03 percent; Hemiptera, 17.30 percent; spiders, 2 percent.
F. C. Clark (1902) found that one stomach examined contained 32 treehoppers, 1 spider, 1 fly, and other insect remains. Fruit juices doubtless form only an inconsiderable part of the hummingbird's diet, but occasionally in fall an Anna's hummingbird may be seen sipping the juice of a persimmon that has been pecked by other birds and has softened on the tree, or the juice of a partially eaten tuna or prickly pear (Opumta).
That the females in the nesting season require some additional mineral constituents in their diet was made clear to me upon seeing a female Anna's hummingbird upon several occasions visit a spot where particles of mortar were scattered. Hovering close to the ground, she appeared to be picking up the small grains and at~ other times would repeatedly plunge her bill into the loose sandy soil near by. Mr. Arnold (1930) tells of seeing Anna's hummingbirds alight on patches of ground where sand and plaster were strewn and seem to be picking up something, which lie did not identify.
The changing seasons of the flowers have made expedient for the hummingbirds a somewhat nomadic existence, aside from true migrations. Perhaps this instinct for change has become so strong in the non migratory Anna's hummingbirds that they are unable to remain in one locality permanently. The sugar syrup containers maintained for their use have been visited by a constantly changing succession of individuals, some remaining only a few days, a few for a period of months, but all have eventually felt some urge more potent than the desire for a sure and easy living.
Behavior: The flight of the hummingbird resembles that of no other bird, but rather that of certain insects, such as dragonflies or hawk moths, though stronger and swifter. Some of the earlier ornithologists expressed doubt of any bird's ability actually to fly backward, suggesting that the hummingbird's withdrawal from the depths of a tubular flower was accomplished by a forward flirt of the tail. A little careful observation would soon remove any skepticism as to its ability to easily fly backward, sidewise or in any other direction. While the tail is rhythmically vibrated forward and backward as the bird probes the flowers, it can be seen that its movements are not at all related to the backward flight, and that it is, in fact, seldom widely opened.
A hummingbird's wings are in almost uninterrupted motion while it is in the air; occasionally it will glide for an instant while in rapid flight. The amplitude of the wing beat is variable, but it often describes an arc of nearly 1800 when the bird poises in the air. Sometimes the wings seem not to rise above the level of the back, but when the bird hovers over a cluster of upturned blossoms they may travel through the upper portion only of the complete arc. The confidence and sureness with which a hummingbird threads its way through a maze of twigs without injury while apparently devoting all its attention to the flowers cause one to admire, but its instant coordination of perception and movement can perhaps best be appreciated by noting the ease and certainty with which it thrusts its bill into a small tubular flower blown by a gusty wind.
That the flight of the hummingbird is by no means effortless, however, may be realized on a hoc day, when one of them, returning to its shaded perch after an extended sortie, will sit for a minute or two with wide-open bill, panting with a violence that shakes its entire body. Though an immense amount of unnecessary flying is done, apparently in sport, the obtaining of food is evidently listed under the heading of work, and a hummingbird will seldom overlook an opportunity to perch, even to the extent of hanging almost upside down while reaching into a flower. The only sound produced by the normal flight of either sex of Anna's hummingbird is a low hum, which rises in volume and pitch when the speed is accelerated and has a slight suggestion of the rustling of silk. In wet weather, how'. ever, one may often hear from a flying hummingbird a sort of clapping noise of short duration, as if it were striking its wings together to rid them of moisture.
The sense of hearing, like that of sight, is keen, and a slight crunching of fallen leaves will evoke an attitude of alert apprehension, just as it does in many other wild creatures. The reaction to a sharp noise, though, is likely to be merely a nervous start, instead of the immediate flight, which is precipitated by any abrupt visible movement. This latter response is so invariable that it may well be regarded as a reflex rather than a volitional action. There seems to be no convincing evidence that the sense of smell plays any part in the discovery of food. A perfumed green-wrapped vial of sugar syrup attracted no attention, though a nearby unperfumed red-wrapped vial was quickly investigated. Some of the most heavily scented flowers, such as the jasmine and the large white blossom of the cactus Trichocereus spachianus, are comparatively neglected. Sense of location is very well developed, and when a bottle of syrup that has been regularly visited by a hummingbird is moved with its support to a different part of the grounds, the bird upon returning will hover in the exact spot from which the bottle was removed, often making several trips before finally becoming convinced.
Most writers have credited hummingbirds with extreme quarrelsomeness among themselves and a tyrannical disposition toward other birds. Careful observation has convinced me that their pugnacity has been greatly exaggerated, especially with reference to birds of other kinds. I believe that a hummingbird pursues other birds for exactly the same reason that a small dog will run after any passing vehicle, but immediately lose interest in it when it stops. Even the smallest passerine birds show no fear of the hummingbirds, nor are they molested if they fail to enter into the spirit of the game. Furthermore, 'I have often seen Anna's hummingbirds forced away from their sugar syrup by house finches or Audubon's warblers without the slightest show of resentment. Of course, a hummingbird that has preempted a certain territory resents any trespassing by other hummingbirds, who usually seem to recognize his rights and seldom dispute them; it is when an interloper resists eviction that the most earnest hostilities occur. Among the migrants in spring and among the immature birds late in summer, however, the constant chases and skirmishes appear to be carried on in a spirit of sport much more than of spite.
Probably because of their constant association among the flowers, hummingbirds show little fear of bees. I have sometimes seen an Anna's hummingbird, in order to reach a supply of sugar syrup, thrust its bill through a struggling mass of the insects. In contrast to this, a few small ants walking around the mouth of the bottle will often keep the bird away entirely. Whether this fear is an instinct founded on the occasional destruction of nestlings by ants is, of course, merely a matter of conjecture. Although the hummingbirds ordinarily treat the bees with indifference, I have watched one attack bees flying around an agave stalk, darting at one after another with open bill as if trying to bite them.
When a male hummingbird preempts a certain territory, he chooses one or more elevated exposed perches from which he can survey his domain and quickly detect trespassers. Sometimes be will use the same perch almost constantly through a whole season, seeking a more sheltered place only in very hot or windy weather; other individuals will alternate between two or more favorite perches, or select new ones at intervals without apparent reason. Acknowledging no family responsibilities, the males spend a large proportion of their daylight hours on these perches; but even the females who are caring for the young unaided seem to have an abundance of leisure in which to rest, preen their plumage, and engage in skirmishes.
Hummingbirds are fond of bathing, especially during the cooler part of the year. Often they seem afraid to enter water of any appreciable depth, but they enjoy bathing in a thin film of water flowing over a flat rock. Most of their bathing is done on dew covered foliage in the early morning and, when available, in the fine spray of a lawn sprinkler. They revel in misty or drizzly rain and are particularly active under such conditions. Carroll Dewilton Scott, of Pacific Beach, Calif., writes (MS.): "Anna's hummingbirds have a strong attraction for moving water. They will hover over irrigation ditches, evidently fascinated by the running water. I have never seen one drink anywhere or take a bath in still water. But the spray of a hose or a fountain is irresistible for a shower bath, even in January. Whenever I spray the garden a hummer is sure to appear." Unusual actions of a bathing hummingbird are described by F. N. Bassett (1924):
On August 17, 1924, while watering my lawn in Alameda, California, I placed the sprinkler in position and had just turned on the water when an adult male Anna Hummingbird (Cripple anna) flew into and poised in the dense spray. After glancing about for a moment he gradually assumed a vertical position and spreading his tail, then slowly settled to the ground, meanwhile drawing the tail back until it nearly reached the horizontal plane, when he actually 'sat' on the grass, the body erect and the tail spread out fanwise behind him. The wings continued to vibrate while in this position, but the strokes were much less frequent than when flying, being just sufficient to maintain a vertical balance. In a few seconds he began increasing the wing strokes and slowly ascended about a foot above the ground where he stayed a moment and then repeated the entire performance several times, after which he flew to a wire overhead.
Sun-bathing is less frequent and appears to be an individual rather than a general custom. Shortly after noon on a hot July day I saw an immature male Anna's hummingbird alight on a bare patch of ground and, heading directly away from the sun, stretch out flat on the soil with wings fully extended and the feathers of the back erected. Again, about two months later, at about the same time of day, the identical action was repeated on the lawn by the same individual. In both instances he remained on the ground less than a minute.
As to the intelligence of hummingbirds. I find no evidence to support W. H. Hudson's contention that they resemble insects more than birds in their mental processes. Their tameness cannot reasonably be attributed to mere stupidity, but rather to justified confidence in their own agility and swiftness and perhaps also in human good will, since their power of discrimination is shown by their noticeable wariness toward cats. In their disposition and temperament hummingbirds are hardly comparable to any other birds but remind one most strongly of chipmunks.
Voice: Of the seven species of hummingbirds found in the State of California, Anna's is the only one that may be said to possess a song. The "song" can hardly he called melodious, being a thin, squeaky warble suggestive of filing a saw. Nevertheless, it is delivered with fervor and remarkable persistence, with little regard for season. This song, which in addition to its use in courtship seems to serve the purpose of a general greeting or challenge, or sometimes merely a form of self-amusement, is peculiar to the males, who begin practicing it almost before their gorgets have started to develop. During the rendition, which often lasts for a rather long time, the bird leans forward on his perch, extends his neck, and holds his bill tightly closed, as far as can be detected at a distance of several feet. The clear, high-pitched, 2- or 3-syllabled whistling call of the male Costa's hummingbird, though less persistently used, appears to be entirely analogous to the Anna's song.
The ordinary notes common to both sexes are similar to those of other species. They consist of the feeding note, a mechanical "tick" or a more liquid chirp uttered at measured intervals as the bird goes from flower to flower; a similar note repeated more rapidly and animatedly while perching and often accompanied by a wagging of the head from side to side, expressing excitement or warning to trespassers; and the shrill twittering, which indicates a chase or skirmish. The begging call of the newly fledged young is much like that of other young birds.
Field marks: Anna's hummingbird is the largest species found within its ordinary range, but there is integradation in measurements with all but the calliope hummingbird, whose small size is usually sufficient to distinguish it from Anna's at any time. Both sexes of Anna's can be separated from the rufous, Allen's, and broad-tailed hummingbirds by the entire absence of rufous or brownish coloring in the plumage. The male differs from the black-chinned and Costa's in the color of its throat and crown and in the fact that the gorget is bordered below by gray instead of white. The adult female usually has a central patch or scattered spots of luminous red on the throat.; otherwise it can generally be distinguished from Costa's by its larger size and darker underparts, and from the black-chinned by its stouter form. In size and general appearance, including the color of the throat, Anna's is probably most like the broad-tailed, but the normal ranges of the two species are entirely separate.
Enemies: The hummingbird is one of the most notable exceptions to the rule that smaller animals must be more prolific than larger ones in order to compensate for an inherently higher mortality rate. Nevertheless, the eggs and young of hummingbirds seem to be subject to more than ordinary vicissitudes. The small size and fragility of the nest, together with its usually exposed situation, make it liable to destruction by storms or accidents, while the long period between the laying of the eggs and the fledging of the young increases the possibility of loss. The e~s are said to be often taken by the California jay (Ape1ocoma californica), and quite possibly they may be eaten by the banded racer (Baecanian laterale) and the alligator lizard (Gerr1wnotw scincicauda), as these reptiles are frequently seen climbing through the foliage of shrubs and trees. In some cases, also, one of the eggs will fail to hatch, even though not disturbed. In their earlier stages, the young are probably threatened by the same enemies previously mentioned, while the spotted skunk (Spilogale pkenaoi) is always a definite peril if the nest is within its reach. Another source of danger to the young birds is mentioned by Mr. Anthony (1923):
The ornithologist visiting San Diego is usually Impressed with the surprising scarcity of nesting birds in Balboa Park, though the surroundings seem to be ideal. It was not until I had been at the San Diego Museum of Natural History a year, that the possible explanation was presented. A swarm of bees that had been installed as au exhibit In the museum was destroyed in a few days by an insignificant ant. This ant, I was told, had in all probability reached our shores with some of the trees or shrubs brought in from South America. It was known as the Argentine Ant. * * *
If bees were killed by ants, why not young birds? Several nests of the Anna Hummingbird (Calypte anna) were located and kept under observation and In every case the young were killed and eaten within two or three days of the time they hatched.
Dependence upon one parent alone would also theoretically increase the chances of failure. All in all, it would seem that the number of young fledged could not represent a very large proportion of the eggs laid. Once the young bird is able to fly, however, the situation is wholly changed, and the fledgling may look forward to the expectancy of a long life. If this were not true, the members of this family could not have maintained their present abundance with their small annual increase. The adult hummingbird seems to have no enemies of importance; certainly no predatory bird could capture it except by accident. On rare occasions a cat will catch one, in all probability an immature individual that has not yet learned caution, as seems to be generally the case among other birds. There are a few accounts of disaster through the agency of an unintentional enemy, such as the following from the manuscript notes of Carroll Dewilton Scott: "On one occasion I rescued a female Anna from impending death. A giant black spider had hung an enormous orb web among pendant eucalyptus limbs about 8 feet from the ground. One spring morning after a foggy night I noticed a female Anna fluttering on the edge of the web. The spider was nowhere to be seen and had not herself entangled the bird who had been snared, possibly, while gathering webs for binding her nest. But. she was hopelessly caught by both wings in the tough, elastic, wet, sticky strands of the spider. After I pulled the webs from her wings she flew to an adjoining tree and sat quite still for several minutes."
That these incidents happen so seldom is a tribute to the hummingbird's alertness and quick perception, since the opportunities for such mishaps are very numerous, and the webs of these large orb-weaving spiders have been proved capable of holding considerably larger birds. Mr. Scott also mentions finding a dead Anna's hummingbird at the base of a window, presumably killed by striking the glass. Eric C. Kinsey states, however, that hummingbirds kept in glass-sided cages soon become accustomed to the glass and do net injure themselves by flying against it.
Of Anna's hummingbird, specifically, it would appear that the most destructive enemy is the exceptional period of cold weather that. comes once in a cycle of years and, with native, plants and animals alike, may overcome the powers of resistance built up to withstand ordinary winters. In this connection Mr. Dawson (1923) says:
Hummigbirds, one sees, even though 'they be so frail, posses an amazing vitality or recuperative power. But it is not too rare an experience to find one stranded, or numbed with the cold; and, to cite the extreme instance, the big freeze of January 2nd, 1913. undoubtedly cut down the resident hummer population of southern California (all Annas) one-half. It is quite worth while upon finding such a waif to try various methods of first-aid. The first expedient is, of course, heat: that of the closed hand may suffice. Or, it may be that the little engine only lacks "gas". Sweetened water, of a pretty strong solution, offered in a pipette, or medicine dropper (pressed upon attention, or flooding the bill until the tongue gets the flavor), will sometimes resuscitate a fallen hummer like a magic potion.
Nevertheless, the hardiness of Anna's hummingbird is greater than might be expected of so small a bird, belonging to a family predominantly tropical. In January 1937, during the most prolonged period of freezing weather in the history of southern California, when the temperature repeatedly fell to 240 F. at my home in the San Gabriel Valley, when ice remained on pools and birdbaths throughout the days and the sky was dark with soot from orchard heaters, half a dozen or more hummingbirds buzzed and twittered about a tall blooming eucalyptus tree and seemed not in the least distressed.
Range: Chiefly California and Baja California; east casually in winter to Arizona and the mainland of Mexico; apparently not regularly migratory.
The breeding range extends north to northern California (Yreka and Mount Shasta. East in this State to Mount Shasta, Pyramid Peak, Big Creek, and the San Bernardino Mountains; and Baja California (San Pedro Martir Mountains). South to northern Baja California (San Pedro Martir Mountains, San Quintin, and San Telmo). The western boundary of the breeding range extends north from this point along the coast of Baja California and California to Red Bluff and Yreka.
During the winter season there is only a slight withdrawal from the northern parts of the summer range, as the species has been recorded at this time north in California to Ferndale and Red Bluff. The most southerly record at this season is Cerros Island, Baja California, about 200 miles south of known breeding areas. During the winter the species also is sometimes common in the southern part of Arizona (Roosevelt Lake and probably Salt River Reservation).
Casual records: This species has been reported from the following other localities in Arizona: Camp Grant (September), Santa Catalina Mountains (October), and the Huachuca Mountains (October). A specimen was taken on February 21, 1934, at Punta Penascosa, Sonora.
Egg dates: California: 86 records, December 21 to August 17; 43 records, February 22 to May 18, indicating the height of the season.