Life Histories 

A chapter from the electronic book:  Life Histories of Familiar North American Birds

Ruby-throated Hummingbird
Archilochus colubris  

Contributed by Winsor Marrett Tyler
[Published in 1940: Smithsonian Institution United States National Museum Bulletin 176: 332-352]

The ruby-throated hummingbird is the only species of hummingbird that enters the eastern two-thirds of the United States. A minute spritelike bird, scarcely bigger than a good-sized insect, it is white below and burnished, sparkling green on the back. The adult male has a gorgeous flaming throat, which, when the sun strikes it, flashes back a deep, glowing orange or red.

The hummingbird moves its wings with such extraordinary rapidity that it seems to be moving through the air between two wisps of mist. Its buzzing wings hold it steady in the air. We see it poised before a flower, most often alone, its body motionless, its tail swaying, as firmly fixed in space as if it were standing on a perch. We see it dart adroitly from one blossom to another, and another--an inch away, six feet away-- passing exactly in front of each one, probing it with its beak, starting and stopping with a jerk, almost, turning at any angle with a sudden twist; or it may shoot off and away, bounding along at full speed. A remarkable power, unbirdlike, more like an overgrown bee.

Spring.--In spring the ruby-throated hummingbird leaves its tropical or semitropical winter quarters and presses northward, keeping pace as the season advances with the opening of its favorite flowers. The bird's preference for some of these is so marked that it seems oftentimes to regulate its migration so as to arrive on the very day of their blossoming. For example, Austin Paul Smith (1915), writing of the Boston Mountains, Ark., says: "The arrival of the 'ruby-throat' and the blossoming of the dwarf buckeye (Aesculus parviflora) were found to be coincident. For it is upon the flowers of this shrub that the ruby-throat finds most of its subsistence for the first two weeks after arrival."

At the start of the northward journey many of the tiny birds fly over a wide stretch of the Gulf of Mexico on their way to the southernmost states. They cross those dangerous waters with little concern, apparently, for W. E. D. Scott (1890) speaks of seeing them "at considerable distance from land" while he was fishing off the Dry Tortugas. "One morning," he says, "I counted six pass by the boat. . . . At such times their flight was direct and very rapid and all were going in a northerly direction. They flew about twenty-five feet above the water and did not appear in any way fatigued, nor show any desire to alight on the boat, as small birds crossing the water so frequently do."

Even in the southern states hummingbirds run the danger of late, killing frosts. "Didymus" (1891) tells thus of the calamity that overcame them in Florida. "It was a warm winter and the early opening of spring brought out the flowers and started myriads of these little creatures on their journey toward the north. Then came that blighting frost--which they could stand, but the 'death of the flowers' was too much for them and they were picked up dead and dying everywhere. They came in unusual numbers and seemed to be nearly all males. After the frost but few were seen. . . ."

On the other hand, Charles B. Floyd (1937) describes an occasion in which some hummingbirds withstood prolonged low temperature and even snow:

The following observations with Hummingbirds. . .made in the Laurentian Mountains of Canada during the last two weeks of May, 1936, are of interest. . . .

On May 20th temperature in the early morning was 22 degrees Fahrenheit above zero after a snowfall during the night of six inches. This snow did not completely melt until late in the afternoon. The temperature the following night was 28 degrees above zero. Early on the following morning the temperature was again 22 degrees. Ice formed in the water-pails and a cold wind blew all day. . . .

During the morning of May 20th the ground and trees were covered with six inches of heavy, wet snow. I spent several hours paddling along the lake-shore on which our camp was located, observing the Hummingbirds and warblers that came there to feed. . . . All these appeared sluggish with cold, and the Hummingbirds fluttered about on the underside of the snow-covered leaves, which were about half developed, apparently capturing minute insects (probably aphids), on which they fed, occasionally dropping to the logs that floated along the shore to secure something so small that I could not determine what it was they were eating. . . .

All the birds permitted so close an approach that I could not use field glasses during these observations. The last day of my stay the Hummingbirds were observed in their usual feeding places and apparently survived the cold weather unharmed.

Usually in spring we meet hummingbirds singly, or at most two or three together, but once in a while we come upon a gathering of migrating birds--almost always of one sex--collected sometimes in a single favored tree. About noon on May 22, 1936, I came upon such a gathering. The birds were in a good-sized red horse-chestnut tree in full flower. They must have numbered more than a dozen, perhaps twice this number. As I came near the tree there burst out a long series of short, sharp, high, jerky notes, the pitch rising and falling, the volume increasing and decreasing. The individual notes had a squeaky quality suggested by the letters sk, but in spite of this I was reminded of the house wren's chatter. By direct comparison, however, the wren's voice was much more mellow, and the delivery more indolent, if one may use the word in reference to that sprightly bird.

Looking in among the branches, I could see here and there two or three birds flying about, making darts at each other. Sometimes a bird or two birds, one chasing the other, flew out and, after flying around the tree a little way, shot in among the branches again. The tree seemed swarming with hummingbirds. Soon the activity calmed down, and the birds perched motionless on small branches, here and there.

The sound quieted also, but rose again energetically when the birds resumed their activity. They probed the blossoms, evidently feeding, but for the most part seemed interested in one another--playfully, or with little hostility. Once I saw two birds fly straight up in the air, close together like mating bees or a swallow feeding its young on the wing, strike at each other, I think, then turn and dive head-downward into the tree. Again a bird flies out from the tree at an approaching bird, utters zzzt-zzz, and drives it off.

The notes varied a good deal. Sometimes a note was so fine, high, and drawn out that it was only a hiss; generally they were very short and clearly cut, either single or double; sometimes they took on a rhythmic form and were repeated over and over, for example z, z, z, z, z, z, zzt, the last note emphasized; and often they came in a long series--single, double, and triple notes all intermixed like a telegraph instrument in action.

It was difficult, owing to their activity among the dense branches, to see the birds clearly, and impossible to count them accurately, but I believe that most, if not all of them were males, their throats in the dark shadow of the branches appearing black.

On the 24th there were fewer birds in the tree--the petals were falling to the ground--and on the 25th only two or three remained.

Jane L. Hine (1894) reports a similar gathering of female birds. She says: "About nine o'clock one spring morning, when lilacs were in bloom, we discovered that the old lilac bush by the well was 'swarming' with Hummingbirds--just come; we knew they were not there a few minutes before. There are five large lilacs on our premises and those of a near neighbor. On investigation I found four of these bushes alive, as it were, with Hummers--all females. The fifth bush, a Persian, they did not favor."

From these observations, and several more in the literature, we may infer that the sexes do not as a rule migrate together, and according to the opinion of many observers the males always precede the females.

Courtship.--In his courtship display the male rubythroat makes use of his marvelous proficiency in flight as well as of the brilliantly glowing feathers of his throat. As we watch him performing such flights as are described below, swinging back and forth along the arc of a wide circle, we get the impression of a bird upheld by a swaying wire; his swings are so accurate and precise that they suggest a geometric figure drawn in the air rather than the flight of a bird. Carl W. Schlag (1930), speaking of the courtship flight, says:

It is comparable to the strutting actions of various species of birds. It is performed several times daily during the breeding season. While the female is quietly feeding from flower to flower, the male will go through this performance, calculated no doubt to impress her more fully with all his charms. Rising up about eight or ten feet above and five or six to one side of her, he will suddenly swoop down, wings and tail outspread, right at her, passing within a few inches of her, the wings and tail making a terrific buzz for a bird so small. Passing her, he rises to an equal height on the opposite side, and turning comes down again in the same way, describing an inverted arc, with that surprisingly loud buzz just as he gets nearest to her. He keeps up this continuous swooping, as I term it, as long as half a minute, at times; at the conclusion of which he usually flies to some near-by perch and rests. During this performance the female feeds quietly at the same cluster of blossoms, not moving any distance away, and sometimes resting on a flower-stalk until he is through.

Mrs. Charles W. Melchner, of Homosassa Springs, Fla., describes a flight that, from its formal, regular character, was probably a variant of the usual courtship display, although there was no dipping--the bird progressing on a level line back and forth--and although Mrs. Melchner did not see a female bird in the vicinity. She writes to Mr. Bent: "Instead of the circular flight he flew in a straight line. Facing the north, he hovered, then moved eastward about 3 feet, then hovered, then moved eastward again for the same distance, continuing thus until he had covered perhaps 25 feet. Then, still facing north, he moved toward the west in the same manner, back to his starting point. I saw him cover the distance four times, twice east and twice west. The fact that he seemed to move sideways makes this a fantastic story, but I think that I have seen the birds that come to our feeders move in almost every direction.

"My attention was first attracted to this flight by the regularity of the humming sound out in the garden. There was a hum, then a second's pause, then another hum, each humming and each pause being of equal length. The humming was made, of course, while he hovered, and lasted perhaps three or four seconds. The pause was very short, just the time it took him to move 3 or 4 feet. The sounds of humming and twittering were so different from usual that I went to the door expecting to see some sort of flight that was out of the ordinary.

"Another performance we witnessed lasted two or three minutes. A male and a female were flying up and down. They were facing each other with tails spread, and there was much twittering. They covered a distance of 5 or 6 feet, and their flight was almost vertical. When he was at the top of his flight she was at the bottom of hers, and when she was at the top he was at the bottom. They were about 2 1/2 feet apart. There was no thrusting at each other until, at the last, they came together for an instant on the windowsill. I was too far away to see if the contact was friendly."

Charles L. Whittle (1937) presents a full account of the actions of a male hummingbird during several weeks before egg-laying time--nine days of watching for a mate, weeks of courtship after she arrived, and after the culmination of his wooing, the almost immediate cessation of display. The bird came to his station in Peterboro, N.H., on May 21 "and began a long vigil lasting until May 30th, believed to be a search for a female." He continues:

This vigil took place from three observation posts overlooking a circular garden, one on an aerial, one on a dead branch of an elm, and a third on a dead twig at the top of an apple tree, all these perches being from fifteen to twenty feet from the ground. For the major portion of each day he occupied these perches, moving from one to another, and while perching he continually moved his head from side to side through an arc of 60 - 70 degrees. One cannot well escape the conclusion that he was searching for a female, since the habit was immediately discontinued upon the arrival of a female at the station on May 30th. Now, for a period of about a month, his attention was devoted to the female and consisted of the usual zooming before her whenever she appeared. . . . On July 2nd a male and a female were seen facing each other in the air about eight or ten inches apart, ascending and descending vertically to a height of about ten feet, and occasionally dropping to the ground for a moment. At times their flights were more or less spiral in character, and such exhibitions were frequent up to July 7th, when Mrs. Whittle observed a pair drop to the ground beside our driveway, where copulation took place. From this time on the males were seen zooming only occasionally, and the vertical flights ceased entirely after the first week in July. . . .

Mating, in the ordinary sense of the word, that is, pairing off well in advance of nest-building and continuing during nidification and raising of the young birds, as far as any evidence observable at this station is concerned, appears not to take place. No preference for a male on the part of the female is indicated until just prior to egg-laying, a period seemingly of three or four days. I have found no evidence that a male's interest in a female one day is manifested towards the same female the following day. All the pretty ways common among many species of mated pairs, often lasting two months at least, are entirely lacking among Hummingbirds. The male appears to be a free lance whose intimate interest in the female is confined to the short period just before and during egg-laying.

Nesting.--The hummingbird's nest, "a model of artistic workmanship," Torrey (1892) calls it, is a compact mass about an inch deep and an inch across, firm in texture, lined with soft plant down, and covered over on the outside with tiny bits of lichen. It is commonly saddled on a limb, usually a small, down-sloping one, often near, and sometimes directly over, water. Wilson (1831) aptly describes the nest when viewed from below as "a mere mossy knot, or accidental protuberance."

Aretas A. Saunders (1936), who made an extensive study of the hummingbird in New York State, describes the situation of the nest thus:

In Allegany Park, the nesting site seems to be always along a brook valley, and in most cases the nest is on a limb that overhangs the brook. Eight nests that I have seen in Allegany Park were on limbs less than an inch in diameter, and one was on a limb a little more than a quarter of an inch through. The limb, in my experience, always slants a little downward from the tree. It is never so high in the tree that it is not sheltered above by other limbs or leafy branches. . . .

I do not suppose that the proximity of the brook has any particular significance in the Humming Bird's nesting except that its favorite flowers grow along the brook and the stream affords an open space. . . .

The [small] size of the limb and its downward slant seem to be aids in protection against possible tree-climbing enemies. . . .

The protection from above is possibly to screen the nest from flying enemies, but chiefly to protect it against heavy storms. . . .

Various kinds of trees are used for nesting, but in Allegany Park the majority of nests found have been in Hornbeams. Of the 11 nests I have observed, and one other reported to me, six were in Hornbeams, two in Yellow Birch, and one each in Sugar Maple, Red Maple and Beech. I have seen nests in Hemlocks in other regions. . . .

The nests found have ranged from five to 18 feet from the ground or water, all but two of them being actually over water.

Saunders (1936) also points out that "the distribution of Humming Birds in Quaker Run valley is governed primarily by the occurrence of Bee Balm, Monarda didyma, the flower upon which they depend chiefly for nectar at the beginning of their breeding season in this region."

Bendire (1895) states that the height of the nest varies "from 6 to 50 feet high, usually from 10 to 20 feet from the ground." Of the nest itself Saunders (1936) says:

The nesting materials are of four kinds, bud scales, plant down, lichens and spider silk. . . . The bud scales make up the bulk of the nest, but by the time it is finished they are entirely covered by the lichens and plant down. . . .

Lichens. . .are put on the outside before the plant down is put in. The lining, in one case at least, was not put into the nest at all until some days after the eggs were laid and incubation begun. The bird continues adding lining material to the nest after the young are hatched, in one case gathering Fireweed down and taking it to the nest when the young were two weeks old. The plants from which down is gathered in Allegany Park are Fireweed, Canada Thistle, Orange Hawkweed and Rattlesnake Root. Possibly others such as Milkweed and various Composites are used also, but the Fireweed seems to be the most commonly used lining material. The bird gathers it directly from the plant. . . .

I have never seen the Hummingbird gathering or working with the spider silk which holds the nest together and fastens it to its limb. The fastening of the nest to the limb is probably an early step in the nest building. But the spider silk is an important item, and in one nest I have seen, was run out and wrapped along two or three twigs that branched out from the point where the nest was fastened, to a distance of 15 inches.

A. Dawes DuBois, in a letter to Mr. Bent, describing the behavior of a female bird while weaving her nest, says: "I stationed myself close to the nest (which was 12 feet from the ground) and watched the bird come and go. She always flew off in the same direction and sometimes was away for five minutes or more. On returning with a tiny tuft of down in her bill, she alighted at once upon the nest and began to tuck the material into its walls on the inner side, using her delicate bill like a needle; then she vigorously worked her body up and down and around about, thereby enlarging and shaping the cavity. Afterward she tucked or adjusted more securely the lichens on the outside. The male bird was not seen at any time."

H. E. Wheeler (1922) says that "the behavior of the female will invariably betray her home. It is easier still to locate the 'house' if the birds are building. . . for the birds keep their territory pretty well cleared of intruding visitors. On one occasion the female Ruby-throat left her nest repeatedly to torment a family of Carolina Wrens, and to pay her respects to a Tufted Titmouse. Otherwise I think I should have never located the tiny nest situated 50 feet above ground, and so thoroughly concealed from view."

In the experience of almost all observers the female parent builds the nest and rears the young unaided by her mate. Bradford Torrey (1892) long ago called attention to this habit in two delightful essays, and Saunders (1936) states in corroboration that "male Humming Birds do not seem to stay in the Quaker Run valley through the nesting season. They are rarely if ever seen after the middle of August."

It is very rare to find any deviation from this habit; hence the following is a very exceptional observation, and it may be that the male's attendance at this nest was merely perfunctory. W. A. Welter (1935), speaking of a nest found in Kentucky, says:

The entire nest, with the exception of bits of lichens that were added later, was built in one day. It is interesting to note that both birds, male and female, worked on this nest that first day. The male evidently was doing his share of the work. This seems to be an unusual circumstance, as ordinarily the male is supposed to scorn such menial duties. . . .

It would seem that the time consumed in nest building diminishes as the season progresses. Perhaps haste is necessary in order that the potential young may be completely developed by the time of fall migration. This need for haste may also have been the stimulant which caused the male in the last case to assist in nidification.

Bendire (1895) says: "I believe two broods are frequently raised in a season, occasionally three perhaps, as fresh eggs have been found as late as August 7. An old nest is sometimes occupied for several seasons and remodeled each year; and should the nest and eggs be taken or destroyed, a second and occasionally even a third and fourth attempt at nesting is made within about a week, and sometimes these subsequent nests are built in the same tree again, or in others close by."

Eggs.--[AUTHOR'S NOTE: Like other hummingbirds, the rubythroat regularly lays two eggs; I have no record of more or fewer. An interval of one day is said by Bendire (1895) to occur between the laying of the two eggs; he says also that the eggs are often laid before the nest is completed. The eggs are pure dead white without gloss and usually elliptical-oval in shape, though occasionally approaching elliptical-ovate, with one end slightly more pointed than the other. The measurements of 52 eggs average 12.9 by 8.5 millimeters; the eggs showing the four extremes measure 14.5 by 9.1, 11.5 by 8.2, and 12.7 by 7.8 millimeters.]

Young.--Bradford Torrey (1892) describing the young hummingbirds newly hatched from eggs no bigger than a pea, says: "Two lifeless-looking things lay in the bottom of the nest, their heads tucked out of sight, and their bodies almost or quite naked, except for a line of grayish down along the middle of the back." Isabella McC. Lemmon (1901) speaks of the young birds as "dark slate-color, with a little yellowish fuzz on the bodies, exceedingly thin necks, three-cornered heads and short yellow bills," and of birds slightly older, Brewster (1890) says: "their bills were perhaps a quarter of an inch long, wide at the base, and in general shape not unlike the bill of a Dendroica, but more depressed."

Bendire (1895) states that the young "are born blind, and do not open their eyes until they are about a week old." These minute, naked, helpless bits of life grow, as Bendire (1895) says, "amazingly fast, and when about ten days old they are about as large as their parents." Torrey (1892), however, speaks of the brood which he watched closely until after they left the nest, as developing more slowly. He says: "Though at least eleven days old, the tiny birds. . .were still far from filling the cup." He describes thus the behavior of the parent as she brooded her young a few days after they had hatched: "It was noticeable that, while sitting upon the young, she kept up an almost incessant motion, as if seeking to warm them, or perhaps to develop their muscles by a kind of massage treatment. A measure of such hitchings and fidgetings might have meant nothing more than an attempt to secure for herself a comfortable seat; but when they were persisted in for fifteen minutes together, it was difficult not to believe that she had some different end in view. Possibly, as human infants get exercise by dandling on the mother's knee, the baby humming-bird gets his by this parental kneading process."

Torrey's birds were hatched on June 30. "On the 12th [of July]," he writes, "just after the little ones had been fed, one of them got his wings for the first time above the wall of the nest, and fluttered them with much spirit." On July 19 the first young bird left the nest. Mr. Torrey continues:

I was standing on the wall with my glass leveled upon the nest, when I saw him exercising his wings. The action was little more pronounced than had been noticed at intervals during the last three or four days, except that he was more decidedly on his feet. Suddenly, without making use of the rim of the nest, as I should have expected him to do, he was in the air, hovering in the prettiest fashion, and in a moment more had alighted on a leafless twig slightly above the level of the nest, and perhaps a yard from it. . . . [Soon] the youngster was again on the wing. It was wonderful how much at home he seemed--poising, backing, soaring, and alighting with all the ease and grace of an old hand.

Illustrating the activity which precedes the flight from the nest, Mr. Torrey says of the other young bird: "He grew more and more restless; as my companion--a learned man--expressed it, he began to 'ramp around.' Once he actually mounted the rim of the nest, a thing which his more precocious brother had never been seen to do. . .exercising his wings till they made a cloud about him."

C. J. Pennock, in a letter to Mr. Bent, describes a young bird "standing erect on the rim of the nest moving his wings slowly--so slowly that I could see the wings distinctly--then rapidly again."

Of the length of time the young birds remain in the nest Forbush (1927) says that it "has been given by different writers as from 6 to 18 days. It may be possible that in the south or during a hot wave in the north, when the female can safely leave her young without danger of chilling them, that she may procure enough food for them to develop wings to the flight stage in a short time; but my New England records of this period run from 14 to 28 days."

During this long period of time the young are fed by regurgitation. Torrey (1892) gives a vivid description of the operation, viewed from close at hand: "The feeding process, which I had been desirous to see, was of a sort to make the spectator shiver. The mother, standing on the edge of the nest, with her tail braced against its side, like a woodpecker or a creeper, took a rigidly erect position, and craned her neck until her bill was in a perpendicular line above the short, wide-open, upraised beak of the little one, who, it must be remembered, was at this time hardly bigger than a bumble-bee. Then she thrust her bill for its full length down into his throat, a frightful-looking act, followed by a series of murderous gesticulations, which fairly made one observer's blood run cold."

When the young bird grew larger, and its beak longer, the parent's beak, Mr. Torrey says, "was thrust into his mouth at right angles," and later, after the young had left the nest, she sometimes passed food directly from her beak to the young bird. "If she found a choice collection of spiders, for instance, she brought them in her throat (as cedar-birds carry cherries), to save trips; if she had only one or two, she retained them between her mandibles."

Carl W. Schlag (1930) says: "In cleaning the nest the hummingbird placed the droppings of the young in a line on the same branch, just above the nest."

Dr. Arthur A. Allen (1930) states that during the first few days after hatching the female feeds the young by merely inserting her tongue into the nestlings' throats and squirting them full of nectar and tiny insects.

Burns (1915) gives the period of incubation as 14 days. Wilbur F. Smith (1920), however, says of a closely watched nest: "On June 2. . .the first egg was laid, and, after an interval of a day, the second was laid. . . . The young hatched on June 15, after eleven days' incubation, during which time the nest was built higher."

Plumages.--[AUTHOR'S NOTE: The young hummingbird is hatched naked, but pinfeathers soon appear, and the young bird is practically fully grown and fully feathered in the juvenal plumage before it leaves the nest. The sexes are unlike in the juvenal plumage. The young male closely resembles the adult female, with white tips on the three outer tail feathers; but the feathers of the upper parts are narrowly edged with grayish buff, the throat is marked with narrow dusky streaks, and the sides and flanks are strongly tinged with brownish buff. The young female is like the young male but lacks the dusky streaks on the throat. Young males begin to acquire one or more ruby feathers on the throat in August and September, but no great progress in this direction is made before they leave for the south, and the adult plumage is assumed before they return in the spring. Dickey and van Rossem (1938) say: "In February and March both adults and young go through a complete molt, and at this time the young males acquire the red throat of maturity. Most individuals have completed this molt by the first week in March."]

Food.--The hummingbird is popularly regarded as solely a sipper of nectar, as it buzzes from flower to flower; as one who might say with Ariel, "Where the bee sucks, there suck I"; but when it comes down to the examination of stomach contents, it is proved that a considerable part of the bird's food consists of insects, chiefly those that come to the flowers the hummingbird visits. Frederic A. Lucas (1892), after examining the contents of 29 stomachs of several species of hummingbirds, comes to the following conclusion:

It would seem to be safe to assume that the main food of Hummingbirds is small insects, mainly diptera and hymenoptera. Hymenoptera are usually present, and small spiders form an important article of food, while hemiptera and coleoptera are now and then found. The small size of the insects may be inferred from the fact that one stomach contained remains of not less than fifty individuals, probably more.

Most of the insects found occur in or about flowers, and my own views agree with those of Mr. Clute, that it is usually insects, and not honey, that attract Hummingbirds to flowers. . . .

In view, however, of the testimony cited at the beginning of this paper, it would seem unquestionable that Hummingbirds do to some extent feed on the nectar of flowers and the sap of trees. . . .

I am much inclined to believe with Dr. Shufeldt that Hummingbirds first visited flowers for insects and that the taste for sweets has been incidentally acquired.

This taste for sweets is very well known to many observers who have supplied hummingbirds with sugar and water placed about their gardens in artificial flowers. Miss Althea R. Sherman (1913), for example, who has experimented in feeding hummingbirds during seven summers, estimated that a single bird consumed "two teaspoonfuls of sugar daily."

Hummingbirds also avail themselves of the sap flowing from holes drilled by sapsuckers. * * * Frank Bolles (1894) speaks of the hummingbirds as constant and numerous visitors to the sapsucker's "orchards."

In order to attract hummingbirds to our gardens Dr. Arthur A. Allen (1930) suggests planting "caragana, pelargonium, tritoma; . . .tiger lilies, painted cups, bee-balms, scarlet salvias, azaleas, and gladiolus;. . .scarlet runners and trumpet vine; . . .horse-chestnuts and buckeyes."

Prof. O. A. Stevens writes to Mr. Bent from Fargo, N. Dak., as follows: "About the earliest flower that the hummingbirds visit here is Ribes odoratum, cultivated from the Missouri River region. The next one, and the one where I always watch for them about May 20 - 25, is Caragana arborescens, an introduced shrub that is much planted here. A little later the native Aquilegia canadensis and Lonicera dioica are available. On a specimen of the latter some of the flowers drooped to the ground, and, as I watched the bird at them, he rested on the ground for a few moments while he probed several flowers. Early in fall the cannas and gladioli are, of course, their favorites. The most natural summer flower seems to be the native Impatiens, and I believe that the hummingbirds' nesting grounds are closely associated with these plants."

Caroline G. Soule (1900) speaks of the activities of a male hummingbird about a bed of nasturtiums. She writes: "Most of his time was spent in slashing off the spurs of the nasturtiums to get at their nectar. We had hardly one perfect nasturtium flower all summer long, owing to his attacks."

Wilson (1831) charmingly notes his experience with the hummingbird as a flycatcher thus: "I have seen the humming bird, for half an hour at a time, darting at those little groups of insects that dance in the air in a fine summer evening, retiring to an adjoining twig to rest, and renewing the attack with a dexterity that sets all our other flycatchers at defiance."

Behavior.--The ruby-throated hummingbird gives the impression of being a nervous, high-strung, irritable little bird. It often resents the presence of other species of birds, however innocent their design may be. It is intolerant also to members of its own species to such a degree that, as a rule, the more hummingbirds there are together, the more excited and hostile they become.

I once saw a hummingbird attack a chimney swift--a strange bird to arouse the hummer's venom. My notes say: "August 2, 1909. This evening I saw Greek meet Greek--a hummingbird chasing a swift. The birds flew overhead rapidly, well above the treetops, the hummingbird a little behind and above. I saw it make a dive at the swift, who avoided the attack by a spurt that carried him well in advance. The hummingbird soon overtook his enemy and made a second swoop down toward him. By this time the birds were so far away that I lost sight of them."

Toward man, however, hummingbirds are usually complaisant, almost to the point of tameness. There are many instances recorded of their being attracted, sometimes in large numbers, to gardens where tubes of sugar and water are put out for their entertainment.

One of the most successful of these feeding stations is the garden of the late Mrs. Laurence J. Webster in Holderness, N.H. Here, for many years, Mrs. Webster studied the birds and provided them with such a bountiful supply of food that, apparently, all the hummingbirds in the vicinity resorted to her garden throughout the summer. She told me that she came to recognize some of the individual birds and, in a few instances, noticed that certain birds would take a long flight, always in the same direction, when they left her garden, and would not return for a long time--evidently visitors from a considerable distance--whereas other birds were in and out of the garden all day. She accustomed the birds to associate the sound of her voice with the presence of food and often called them to a vial she held in her hand by whistling the "phoebe" note of the chickadee.

Her garden on August 5, 1937, when Mr. Bent and I visited her, was whirring with hummingbirds--at least 40, we thought. Mrs. Webster covered the scattered feeding tubes and, seated at an open window beside Mr. Bent, who held a filled tube in his hand, gave the chickadee call. A bird came up out of the garden, poised a moment, then alighted on Mr. Bent's finger.

All day a deep hum sounds through her garden, rising or falling in intensity as birds come together or feed from the vials undisturbed, alone. At dusk, as one by one the birds leave the garden, the pitch of the whirring wings lowers, gradually dying down to a dull, tranquil sound, until "at twilight's hush" the last bird has gone.

It was in this garden that the motion pictures, described below, were taken.

The remarkable flight of the hummingbird, during which the wings move so rapidly that they are practically invisible, has attracted a great deal of interest and conjecture. Some observers maintained that the birds sometimes fly backward when leaving a flower--Bradford Torrey, for example, seemed to have had no doubt on the subject (see above); other observers, however, objected on mechanical grounds that no bird can fly backward. It remained for motion photography to settle the question.

That the hummingbird does fly backward has been definitely proved, and the manner in which backward flight is accomplished has been demonstrated by means of motion pictures taken in 1936 by a new application of photography. Dr. Harold E. Edgerton took advantage of the intermittent flashes in a low-pressure tube in which the flashes occur for 1/100,000 of a second with a period of darkness between them lasting 1/500 of a second. He used a constantly moving film, geared so that a new bit of film came opposite the lens of the camera at each flash, and thus secured about 540 pictures a second. Pictures of hummingbirds in flight taken in this way, when thrown on a screen, apparently reduce the speed of the birds' wing beats to that of a leisurely flying gull and make it possible to study the flight of the bird in detail.

Dr. Charles H. Blake examined with great care the films taken of hummingbirds in flight and found that the birds beat their wings 55 times (completed strokes) a second when hovering, 61 a second when backing, and as rapidly as 75 a second when progressing straightaway. Probably this last figure would be found to increase as the bird gained speed, if the camera could keep the bird in focus. Dr. Blake calculated that, during hovering, the wing tips moved at the rate of 20 miles an hour, and he also learned that the bird is in flight before it leaves its perch (the takeoff took 0.07 second) and pulls the perch after it a little way, a phenomenon that Mrs. Webster had suspected from feeling the birds leave her hand.

Dr. Blake kindly explained to me the mechanism of backward flying thus: In backing away from a flower or feeding tube the hummingbird stands almost vertically in the air with its tail pointing downward and a little forward. In this pose its wings beat horizontally, and what would be the downward half of each complete wing stroke if the bird's long axis were parallel to the ground forces the air forward, away from the bird's breast in its upright position, and drives the bird backward. Then, on the return half-stroke, the whole wing is rotated at the shoulder joint so that its upper surface strikes the air, and, driving it downward, balances the pull of gravity. Dr. Blake also points out that the distribution of weight in the hummingbird's wing is evidently favorable to a very low inertia upon which the quick reversal of motion depends, the weight being concentrated close to the body by reason of the short, heavy humerus.

The following quotation shows the high rate of speed the hummingbird may attain by the lightninglike strokes of its wings. H. A. Allard (1934), who was making a fast trip by auto out of Washington, D.C., says: "Not far out of Warrenton we had settled down to a speed of fifty miles per hour on highway 211, when a Ruby-throated Hummingbird (Archilochus colubris) suddenly paralleled our course along the side of the roadway as if deliberately racing with us. It actually passed us for a short distance keeping straight with our course, then swerved away. Its speed appeared to be somewhere between 50 - 60 miles per hour."

Hummingbirds have been seen so frequently hovering before the brilliant red flowers in our gardens--trumpet vines clambering over the porch, salvias gleaming scarlet in the flower beds--that it has been assumed the birds have a preference for the the color red. However, the extensive investigations of Andrew L. Pickens (1930) bring out the fact that it is the brightness of color--its conspicuousness against the background--that draws the hummingbird to a flower. He says:

It is easy to perceive that Hummingbirds prefer the intensity of color shades rather than the paleness of color hues. . . .

[But] the question is one that cannot be decided by mere rule of spectrum or pigments. There is so to speak a relativity of colors. . . .

Red being the complement of green is the most conspicuous color that a flower can show. . . .

Orange, while not so brilliant, is more showy in deeply shaded swamps and woods than is red. . . .

Green flowers are too inconspicuous among foliage. In certain contrasting desert backgrounds, or on the sere dry-season prairies it should have value. Thus, while no green Hummingbird flowers are known in the East, Nicotiana paniculata, one of the greenest flowers I know, is much frequented in the West, during the dry season at least. . .

Complete lists [of flowers] would probably show red, the sharpest contrast to green, a favorite everywhere, with orange in some favor in tree-shaded regions and a neglected color like green rising in sun-browned territory.

Experiments made by Miss Althea R. Sherman (1913) to test the "supposedly erroneous theory which had been published to the effect that Hummingbirds show a preference for red flowers: indicated conclusively that hummingbirds visited the bottles she placed about her garden if they contained syrup, whether or not they simulated a flower in shape or color. The birds associated even an untrimmed bottle with food, just as they soon came to recognize Miss Sherman herself as a supplier of food.

Speaking of pollination Saunders (1936) says that the bee balm "is the most important Humming Bird flower in Allegany Park. The anthers and stigma brush the crown of the Humming Bird's head as the bird probes the flower. The pollen is bright yellow, so that most summer Humming Birds appear to have yellow crowns."

Pickens (1927) points out in detail an interesting adaptation, insuring cross fertilization by the hummingbird, in the flower of Macranthera lecontei. He says: "Of all the forms that I have studied this is the most exclusively Hummingbird flower, and I recall seeing no other honey-gatherers in its vicinity."

Voice.--The notes that come from the hummingbird's tiny throat are high pitched and have a petulant quality, reflecting the bird's irritable nature. Sometimes the notes are angry-sounding, mouselike squeals; sometimes they are run into a nervous, fretful chattering, always very sharp and clear, though by no means loud, and delivered in a jerky, excited manner.

A lone hummingbird is usually silent, except for the buzzing of its wings, but when several birds are together they often become very voluble and quarrelsome and jerk out their notes, now arranged in emphatic phrases, squealing and chattering back and forth as if they were carrying on an animated controversy in a jabbering language.

Sometimes a single bird approaches another one poised before a flower and disputes its right to the place. Both then express their mutual hostility by beginning to jabber, and after a dart at each other and a fight, or at least a whirling about in the air, the winner of the encounter returns quietly to the flower. Thus when we stand close to a company of hummingbirds we hear the sound of their voices rising and falling in irregular waves--anger or resentment mounting up again and again and, in between, a short truce, marked by the peace of humming wings.

The pitch of the notes is invariably high, but it varies a good deal. Sometimes a note rises almost to a piercing whistle, and often the tone suggests the steely voice of the chimney swift.

In the phrases the notes are arranged in many ways; usually both squeals and short chips are combined, but either may be given alone, and the pitch of either one may run upward or downward. The short notes, when uttered alone are generally in series, repeated without change over and over, coming in twos, threes, or more again and again, the last note of each series commonly accented sharply. When the squeals and chattering are interspersed they often fall into a very pleasing rhythm. For example, a form often given when one bird joins another is a single sharp note followed by a long, descending chatter.

The chief characteristics of the hummingbird's voice are the sharply cut, emphatic enunciation and the attenuated quality.

Mary Pierson Allen (1908), speaking of a fledgling hummingbird that she fed with sweetened water, says: "He had his mother's zip-zip, which meant flowers or happiness, and a plaintive baby peet, peet, when he wanted food."

Field marks.--Audubon (1842) states: "If comparison might enable you, kind reader, to form some tolerably accurate idea of their peculiar mode of flight, and their appearance on wing, I would say, that were both objects of the same colour, a large sphinx or moth, when moving from one flower to another, and in a direct line, comes nearer the Humming-bird in aspect than any other object with which I am acquainted."

It is true that the ruby-throated hummingbird bears not the slightest resemblance to any other bird occurring in the eastern and middle United States. It is sometimes mistaken, however, for the hawk moths, which hover about flowers in the manner of a hummingbird.

The adult male differs from the female and the immature bird in possessing a highly colored throat, which gleams in the sunlight like a glowing coal, oftentimes nearer coppery brass than true ruby. The male's tail is plainly forked and is not marked by the white spots that distinguish the rounded tail of the female and the young bird.

Enemies.--In addition to the dangers of migration, notably the occurrence of frost when the hummingbird overruns the advance of spring, there are other hazards, chiefly of an accidental nature, imperiling the life of the bird.

Ralph E. Danforth (1921) speaks of a bird caught in "a pendulous mass of cobweb" from which he freed it with some difficulty, and Bradford Torrey (1903) relates what he calls "a pretty story" told to him by an observer whom he describes as "a seeing man." The man, hearing "the familiar, squeaking notes of a hummer, and thinking that their persistency must be occasioned by some unusual trouble, went out to investigate. Sure enough, there hung the bird in a spider's web attached to a rosebush, while the owner of the web, a big yellow-and-brown, pot-bellied, bloodthirsty rascal, was turning its victim over and over, winding the web about it. Wings and legs were already fast, so that all the bird could do was to cry for help. And help had come. The man at once killed the spider, and then, little by little, for it was an operation of no small delicacy, unwound the mesh in which the bird was entangled."

Joseph Janiec sends the following story to Mr. Bent: "While I was wandering through a large hollow one June afternoon, my attention was attracted to the unusual waving of a pasture thistle. No air was stirring, and my curiosity prompted me to ascertain the cause of the movements. As I approached the thistle I noticed what I at first supposed to be a large dragonfly impaled on the prickly purple flower; closer examination, however, revealed a male ruby-throated hummingbird stuck to the flower, his wings not being involved in the contact but his stomach feathers adhering to the prickly, pointed stamens. Cutting off the flower, I carried it and the bird home and carefully removed the bird. Although it lost a few feathers in the operation, the little bird flew away unharmed."

There is a surprising record from California telling of the capture of an unidentified species of hummingbird by a fish. Mary E. Lockwood (1922) says, quoting from a letter: "We were seated by the lotus-pool when a hummingbird flew and hovered over the pool. Suddenly a bass jumped from the water and swallowed the hummingbird."

George H. Lowery, Jr. (1938) reports the following apparently unique record:

I shot a female Eastern Pigeon Hawk (Falco columbarius columbarius) on April 16, 1937, at Grand Isle, off the coast of Jefferson Parish, Louisiana. Upon examination of its stomach contents, I was surprised to find the identifiable remains of a Ruby-throated Hummingbird (Archilochus colubris). Later, on a visit to Washington, D.C., I discussed the matter with Mr. Clarence Cottam, Director of the Food Habits Division of the Bureau of Biological Survey. With his permission and the assistance of Mr. Robert McClanahan of the Food Habits offices, I went through the extensive records of that division and found no species of hummingbird had ever heretofore been recorded from any bird stomach.

L. T. S. Norris-Elye writes to Mr. Bent: "During the summer of 1934, James Ashdown, Jr., and his mother were walking in the woods at Kenora, Ontario, and heard a continuous rattling. Investigation showed it to be a male ruby-throated hummingbird on the ground, with a huge dragonfly on the bird's back; it had seized the bird by the neck. They drove the dragonfly away, picked up the bird, and held it in the palm of the hand for several minutes, after which it flew away.

"We have had instances of frogs capturing and swallowing ruby-throats, one at Gull Harbor and one at Gimli, Lake Winnipeg. The Gimli case was observed by my friend Hugh Moncrieff, who captured the frog (leopard) and had some boys cut it open to recover the bird, while he took some good motion pictures of the operation."

Fall.--Taverner and Swales (1907) describe vividly a great concourse of migrating hummingbirds on Point Pelee, Ontario, Canada:

The first three days of September in 1906 were notable for the vast numbers of Hummers present. In certain low slashings in the open woods were luxuriant growths of Jewel Weed (Impatiens sp?) standing nearly shoulder high and so dense that to enter it one had to force his way through. It was simply spangled with blossoms, and all about and over it hovered and darted hundreds of Hummingbirds. From some little distance, as we approached such clumps, we were aware of innumerable little twitterings that followed each other so rapidly as to scarce be separable, one from another, and so fine, sharp, and high in pitch that it took a little effort to realize that it was real sound and not imagination or ringing in the ears. Underlying this was a low hum that arose from the vibrations of many little wings. Approaching closer, the pugnacious little mites were all about us, chasing each other over the smooth rounded surface of the jewel weed or darting angrily at us from this side or that, with furious chatterings that made one instinctively cover the eyes, or involuntarily flinch at the expected impact of their sharp, rapier-like little bills. . . . All these birds were juveniles. . . .

Keays noted that in 1901 the Hummingbird was the only-species that did not turn back when, in migrating out the Point, it reached the end. We verified this many times. The final end of the Point stretches out for a couple of hundred rods, in the form of a long, low, more or less winding and attenuated sand spit. Stationed about half way out on this, it was most amusing to watch the little mites come buzzing over the last half of the red-cedar bushes and then drop down towards the ground and, without pause or hesitation, follow every winding of the ever-changing sand to its extreme end, and then, with a sudden and resolute turn, square away for Pelee Island, just visible on the horizon. Dr. Jones was stationed on the opposite islands from August 26 to September 2, 1905, and makes the following statement as to the movements of the species over the waters of the lake: "Hummingbirds were passing during the daylight, and all those noted were flying very low. In fact they dropped down between the waves for protection from the wind, which was quartering, or at right angles to their line of flight and seemed to disturb them. I noticed that in the strong westerly wind, all birds headed southwest, but always drifted south."

I remember seeing, in Lexington, Mass., on two or three occasions in September, a single hummingbird, a dozen feet from the ground, bounding past me through open country, undulating in long, low waves as it held a rapid course toward the southwest--the line of migration in autumn through eastern Massachusetts. And again in May I once saw a lone bird steering due north, or a little east of north, flying, straight as an arrow, not 2 feet above the grass blades.

*Original Source: Bent, Arthur Cleveland. 1940. Smithsonian Institution United States National Museum Bulletin 176: 332-352. United States Government Printing Office

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