In wild portions of the country, where natural facilities are still afforded to these Swifts, they are occasionally found breeding within the hollows of decaying trees. Mr. George A. Boardman, of St. Stephen, N. B., writes that in his neighborhood this bird continues to build in the hollows of trees. He adds, that in the summer of 1863 he found them building within a hollow birch. He also met with one of their nests built against a board in an old winter logging-camp, at a distance from any chimney. Mr. Ridgway has also met with the nest of this bird inside the trunk of a large sycamore-tree, and also mentions finding another attached to the planks of an outbuilding, in the Wabash valley of Southeastern Illinois.
Mr. J. A. Allen found this species quite numerous in Kansas, where it was breeding chiefly in the hollow trees of the forests, which it always seems naturally to prefer to chimneys, to which it is compelled to resort, in most of the longer settled districts, or else wholly to abandon the country.
The Chimney Swallow is known to breed throughout the Central and Northern States, from Virginia to Canada. Dr. Woodhouse states that he found this species very abundant throughout the Indian Territory, as also in Texas, and New Mexico, even to California. It was not, however, taken at San Antonio by Mr. Dresser, nor in any portion of Texas, and was not procured by any of the naturalists in the other Western expeditions.
The Chimney Swallow is crepuscular, rather than nocturnal, in its habits, preferring to hunt for its insect prey in dull and cloudy weather, or in the early morning and the latter part of the afternoon. In this it is probably influenced by the abundance or scarcity of insects, as it is not unfrequently to be seen hawking for insects in the bright glare of noon. When they have young, they often continue to feed them until quite late at night. They are not, however, to be regarded as nocturnal, as they are only known to do this during a brief period.
The nest of this species is a very peculiar and remarkable structure. It is composed of small twigs of nearly uniform size, wrought and interwoven into a neat semicircular basket. In selecting the twigs with which they are to construct their nests, the Swifts break from the tree the ends of living branches, which they gather with great skill and adroitness while on the wing. Sweeping upon the coveted twig somewhat as a Hawk rushes on its prey, it divides it at the desired place, and bears it off to its nest. This is a well-attested fact, familiar to all who have ever watched these birds in the early morning as they are at work constructing their nests.
Each one of these twigs is strongly fastened to its fellows by an adhesive saliva secreted by the bird, and by the same cement the whole structure is made to adhere to the side of the chimney in which it is built. This saliva, as it dries, hardens into a tough glue-like substance, as firm even as the twigs it unites. In separating nests from the sides of chimneys, I have known portions of the brick to which it was fastened part sooner than the cement. When moistened, however, by long-continued rains, the weight of their contents will sometimes cause these nests to part, and the whole is precipitated to the bottom. The young birds cling very tenaciously to the sides of the chimneys with their bills and claws. They not only are often able, in these accidents, to save themselves from falling, but even at a very early age can cling to the sides of the chimney and work their way to the top. They always leave their nest and climb to the upper part of the chimney several days before they can fly, and are there fed by their parents.
Occasionally the young birds fall to the bottom of the chimney, out of the reach or notice of their parents. I have never been able to induce them to take any food, although they keep uttering pitiful cries of hunger. In such cases the young birds placed on the roof near their native chimney soon manage to climb to its base, and there receive the aid of the old birds.
Their eggs are four in number, somewhat elliptical in form, though somewhat less obtuse at one end than the other. They are of a pure white color, and are never spotted. They vary but little in size or shape, and measure from .75 to .81 of an inch in length, and from .50 to .55 in breadth.
In New England the Chimney Swallow raises but one brood in a season. In Pennsylvania it is said to have two.
Cypselus vauxi, Townsend, J. A. N. Sc. VIII, 1839, 148 (Columbia River).—Ib. Narrative, 1839. Chætura vauxi, DeKay, N. Y. Zoöl. II, 1844, 36.—Baird, Birds N. Am. 145, pl. xviii.—Sclater, Cat. 282.—Ib. P. Z. S. 1863, 100 (Guatemala).—Kennerly, P. R. R. x, b, pl. xviii, f. 2.—Cooper & Suckley, 165.—Cooper, Orn. Cal. 1, 1870, 351. Acanthylis vauxi, Bonap. Comptes Rendus, XXVIII, 1854; notes Delattre, 90.—Cassin, Ill. I, 1855, 250.—Newberry, Zoöl. Cal. and Or. Route, 78; P. R. R. Surv. VI, 1857.
Sp. Char. Light sooty-brown; rump and under parts paler; lightest on the chin and throat. Length, 4.50; wing, 4.75; tail, 1.90.
Hab. Pacific coast, from Puget’s Sound to California. West coast to Guatemala (Scl. P. Z. S. 1863, 100); Yucatan (Lawr. Ann. N. Y. Lyc. IX, 204).
This species bears a very close resemblance to the common Chimney Swallow of the Eastern States, being only readily distinguishable by its much smaller size, 4.50 inches instead of 5.25. The wing, too, is nearly an inch shorter. The tarsus and the middle toe, however, seem absolutely longer. The rump is a little paler than in C. pelagica, as well as the under parts, where the chin and throat are lighter, almost dirty white, and gradually becoming a little darker behind, although even the hinder part of the belly is much lighter than the back, even in strong contrast, instead of being of the same color with it. Guatemalan specimens are much darker.
Habits. This western Swift was first discovered by Mr. Townsend on the Columbia River, where he found it having the primitive habits of the eastern species, and breeding in hollow trees, forming a nest in a similar manner, and laying four pure-white eggs. It differs from the common bird in its smaller size and lighter color. It is said to occur from Puget Sound to California.
Dr. Cooper met with these birds May 4, 1864, in the Coast Range, twelve miles south of Santa Clara. He was of the opinion that they had nests in hollow trees at the summit of the mountains, but he was not able to find any. He did not observe any at Fort Vancouver in the summer of 1853, nor did he learn whether these birds are found in the central valleys of California. In 1866 they were observed to make their first appearance at Santa Cruz on the 4th of May, though as they rarely descended to the town they might have been on the hills earlier than this. On the 5th of October he observed five of them, in company with a large flock of Hirundo bicolor, spending the morning in hunting insects near the town. They were apparently delayed in their migration southward by a thick fog and cold south-wind. They may have been a late brood from the north.
Dr. Kennerly obtained a single specimen of this species at the Straits of Fuca, showing that these birds sometimes extend their migrations up to the 49th parallel. Neither Dr. Suckley nor Dr. Cooper was able to find this Swift anywhere in Washington Territory.
Dr. Newberry observed this species quite common in California, but could obtain no specimens, owing to the height at which they flew. He saw nothing of it in Oregon.
Two specimens of this species obtained in Mexico by M. de Saussure are in the collection of Dr. Sclater.
Mr. Ridgway saw on the Truckee River, near Pyramid Lake, in May, 1868, what he supposes to have been this species. It was not common, only a few individuals being observed every evening just before dusk, flying overhead exactly in the manner of Chimney Swallows (C. pelagica), which they also exactly resembled in appearance. They flew so high that specimens could not be obtained. They were entirely silent, and appeared at no other time than in the evening, in these respects differing strikingly from the eastern species.
Char. Least of all birds; sternum very deep; bill subulate, and generally longer than the head, straight, arched, or upcurved. Tongue composed of two lengthened cylindrical united tubes, capable of great protrusion, and bifid at tip; nostrils basal, linear, and covered by an operculum; wings lengthened, pointed; first quill usually longest except in Aithurus, where it is the second; primaries, 10; secondaries, 6; tail of ten feathers. Tarsi and feet very diminutive, claws very sharp. (Gould.)
There is no group of birds so interesting to the ornithologist or to the casual observer as the Humming-Birds, at once the smallest in size, the most gorgeously beautiful in color, and almost the most abundant in species, of any single family of birds. They are strictly confined to the continent and islands of America, and are most abundant in the Central American and Andean States, though single species range almost to the Arctic regions on the north and to Patagonia on the south, as well as from the sea-coast to the frozen summits of the Andes. Many are very limited in their range; some confined to particular islands, even though of small dimensions, or to the summits of certain mountain-peaks.
The bill of the Humming-Bird is awl-shaped or subulate; thin, and sharp-pointed; straight or curved; sometimes as long as the head, sometimes much longer. The mandibles are excavated to the tip for the lodgement of the tongue, and form a tube by the close apposition of their cutting edges. There is no indication of stiff bristly feathers at the base of the mouth. The tongue has some resemblance to that of the Woodpecker in the elongation of the cornua backwards, so as to pass round the back of the skull, and then anteriorly to the base of the bill. The tongue itself is of very peculiar structure, consisting anteriorly of two hollow threads closed at the ends and united behind. The food of the Humming-Bird consists almost entirely of insects, which are captured by protruding the tongue in flowers of various shapes without opening the bill very wide.
The genera of Humming-Birds are very difficult to define. This is partly owing to the great number of the species, of which nearly four hundred and fifty have been recognized by authors, all of them with but few exceptions diminutive in size and almost requiring a lens for their critical examination, so that characters for generic separation, distinct enough in other families, are here overlooked or not fully appreciated. A still greater difficulty, perhaps, is the great difference in form, especially of the tail, between the male and female, the young male occupying an intermediate position. The coloration, too, is almost always very different with sex and age, and usually any generic characters derived from features other than those of bill, feet, and wing do not apply to the females at all.
In the large number of species of Humming-Birds arranged in about one hundred and thirty genera, only two subfamilies have been recognized, as follows:—
Phæthornithinæ. Anterior toes connected at the base. No metallic lustre to the dull plumage.
Trochilinæ. Anterior toes not connected at the base. Plumage brilliant, with more or less of metallic lustre, at least in the males.
The first-mentioned subfamily embraces five genera, and about fifty species, none of which are found in the United States. The Trochilinæ count nearly four hundred species and one hundred and twenty-five genera, and in the absence of any successful attempt to arrange them in subordinate groups, the difficulties of determination on the part of the tyro may readily be imagined.
Of the seven genera accredited to North America, with their ten species, we cannot pretend to do more than present an artificial analysis, which may serve to define them as compared with each other, but bear little reference to the family as a whole. The characters are selected partly from the shape of tail and partly from color.
Common Characters. All the North American Trochilidæ have metallic green backs, excepting Selasphorus rufus, this color extending over the top of head, except in Calypte (metallic red and violet), and Heliopædica (bluish-black). The latter alone has a white stripe through the eye. Atthis heloisæ alone has the tail tipped with white in the male. Females of all the species except Heliopædica have tail tipped with white; all have it rounded. All females lack the metallic throat. The males of the several genera belonging to North America may be distinguished as follows:—
A. Top of head green.
Feathers of throat not elongated.
Tail rounded or slightly emarginated, the feathers broad, rounded, and metallic rufous-purple, or greenish-blue. Wing more than 2.50 … Lampornis.
Tail more or less forked; feathers pointed, narrow, and without rufous or blue. Wing much less than 2.00 … Trochilus.
Throat-feathers elongated laterally into a kind of ruff. Tail-feathers edged or banded with cinnamon at base.
Tail cuneate, the outer primary attenuated at end. Innermost tail-feather green above.
Tail dusky at end … Selasphorus.
Tail tipped with white … Atthis.
Tail nearly even, and emarginated. Outer primary not attenuated at end. Innermost tail-feather brown above … Stellula.
B. Top of head metallic red or violet.
Metallic feathers of side of throat much elongated … Calypte.
C. Top of head bluish-black; a white line through eye.
Metallic feathers of side of throat not elongated.
Tail nearly even, and slightly emarginated. Lateral feathers very broad and obtuse at end … Heliopædica.
We have included Lampornis in the list of United States genera on exceedingly doubtful evidence of the occurrence of L. mango, which was said to have been taken at Key West, and sent to Mr. Audubon, who figured it. The species, however, proves to be one belonging to Brazil, and not the Jamaican form (L. porphyrura, Gould), which might possibly have straggled there.
In reference to the large number of species of Trochilidæ, it may be well to remark that many differ by very slight, sometimes quite inappreciable characters, and are to be looked on as only climatic or geographical varieties. All those given for the United States are, however, well marked.
Additional species of Trochilidæ will doubtless yet be detected within our limits, especially in Arizona, New Mexico, and Southern Texas, where almost any of the Mexican table-land species may be looked for, such as Calypte floresi, Calothorax cyanopogon, etc. South Florida will probably yet furnish to us the Bahaman Doricha evelynæ.
The following synopsis expresses, perhaps, a more natural arrangement of the genera:—
A. Nasal operculum entirely covered by the frontal feathers; base of the bill narrow.
a. Tail forked, and unvariegated in the male. Outer primary strongly bowed, or curved inward at the end.
Stellula. Tail deeply emarginated in ♂, somewhat doubly rounded in ♀, but outer feather not longest; the feathers spatulate; outer primary very strongly bowed, and very broad at end. ♂. Gorget feathers linear, much elongated; only their terminal half colored; crown green like the back. ♀. Similar in form, but the intermediate feathers of tail longer than the external, instead of shorter.
Trochilus. Tail deeply emarginated in the male, the feathers attenuated toward tips; doubly rounded in ♀, and broader; outer primary strongly bowed, but narrow at end. ♂. Gorget feathers broad, short, squamate; colored blue or crimson to their bases. Crown green like the back.
Calypte. Tail as in Trochilus, but the external feather abruptly narrower than the next, with its edges nearly parallel. Outer primary as in Trochilus. Crown metallic (violet or crimson) like the throat. Female like that of Trochilus.
b. Tail rounded or graduated, and variegated in the male. Outer primary only slightly bowed, and narrow at end, except in ♀ of Atthis.
Selasphorus. Tail graduated in the ♂, the feathers attenuated at ends. Outer primary abruptly attenuated, the end turned outwards. Gorget feathers broad, elongated laterally, rose-purple or fire-color; crown green like the back; tail-feathers edged with rufous. ♀ with tail less graduated, and the feathers broader at ends. Outer primary broader, and not attenuated and turned outward at end.
Atthis. Sexes alike in form. Tail rounded; outer primary bowed at end, rather narrow in the ♂. Gorget feathers much elongated, posteriorly and laterally; tail-feathers tipped with white.
c. Tail rounded, or slightly emarginated, and usually unvariegated in either sex; the feathers very broad, and rounded at the ends; primaries normal, the outer broad to the end, and moderately bowed.
Lampornis. 113 Bill cylindrical, considerably curved. Wing very long, reaching to, or beyond, the tip of the very broad tail. Size large (wing, 2.50, or more). The male dark-colored (green or black) beneath. Sexes sometimes alike (in West Indies).
B. Nasal operculum entirely uncovered; base of bill very broad. Female with tail-feathers not tipped with white.
Heliopædica. Sexes alike in form. First primary longest, much bowed toward end. Tail more than two thirds the wing, nearly square (a little emarginated in the ♂, slightly rounded in the ♀), the feathers very broad, rounded at ends. Color, metallic green above, white or rufous glossed with green below; a conspicuous white post-ocular stripe, and an auricular one of black beneath it. ♂. Forehead and chin black or metallic blue; throat rich metallic green. ♀. Forehead dull brownish-green; chin and throat white, glossed with green, or plain ochraceous; tail plain bluish-black or purplish-rufous, the middle feathers more or less green.
Thaumatias. Sexes alike in form and color. General form of Heliopædica, but tail emarginated, instead of rounded. Color nearly uniform green, with or without white throat and abdomen. Tail grayish-dusky, with an obscure subterminal band of black (with basal three fourths white in T. chionurus).
Habits. The habits and manners of the whole family of Trochilidæ are, in many striking respects, entirely peculiar to themselves, and without any known correspondence or close resemblance to those of any other kinds of birds, either in America or elsewhere. This family is found exclusively in America, either in the islands or on the continent, and number in all not far from four hundred species, distributed into various subdivisions and genera, but all possessing, to a very large degree, the same common peculiarities, of which the well-known Ruby-throat of eastern North America may be taken as eminently typical. The habits and peculiarities of this numerous family have been closely studied, and many valuable facts in relation to them have been contributed by various naturalists; by none, perhaps, with more intelligent attention than by the eminent Swiss naturalist, M. H. de Saussure, in his visit to the West India Islands and Mexico, to whose observations we are largely indebted.
On the first visit of this naturalist to a savanna in the island of Jamaica, he at once noticed what he at first took to be a brilliant green insect, of rapid flight, approaching him by successive alternations of movements and pauses, and rapidly gliding among and over the network of interlacing shrubs. He was surprised by the extraordinary dexterity with which it avoided the movements of his net, and yet more astonished to find, when he had captured it, that he had taken a bird, and not an insect.
He soon satisfied himself that this entire family not only have the form and aspect of insects, but that they have also the same movements, the same habits, and the same manner of living, with certain insects. Their flight is exactly like that of an insect, and in this respect they form a remarkably exceptional group among birds. When we notice their long wings in our cabinet specimens, we naturally suppose that they use these instruments of flight in the same manner with the Swallow or the Swift. Yet investigation shows that, so very far from this, these wings, comparatively so very long, vibrate even more rapidly than do those of birds with proportionately the smallest wings, such as the Grebe, the Loon, and the Penguin, and that, more than this, they vibrate with an intensity so vastly superior, that they become wholly invisible in the wonderful rapidity of their movements.
The altogether exceptional character of their flight is a subject for never-ceasing astonishment. Until we actually witness it, we should never conceive it to be possible for a bird to vibrate its wings with so great a rapidity, and by them to support itself in the air in the same manner with the Anthraces and other aerial insects. This feat is rendered all the more surprising by the extreme narrowness of the wing and the comparative weight of the body, which is quite considerable, on account of the compactness of the flesh and bones, and the small size of the birds themselves, whose wings displace but a small quantity of air. The resistance of the air to the stroke of the wing of a bird should be, not in proportion to the surface of that wing, but to its square, or even to its cube, if the movement is very rapid. Hence it follows that a due proportion being required as between the weight of the body and the surface of this organ, a small bird cannot keep itself poised in the air except by means of vibrations more rapid than those of a larger kind. This is, without doubt, one explanation of the fact that Humming-Birds, in their flight, are so insect-like. They pass from bush to bush as if suspended in the air, and pause over each flower, vibrating their wings, in precisely the same manner with the Sphinxes, and with the same humming sounds.
The flight of the Humming-Bird is of two kinds. One of these is used for a horizontal movement, and is so rapid that one can hardly follow it with the eye. This is accompanied by a kind of hissing sound. The other seems to keep the body in the air immovable, in one spot. For the latter purpose the bird assumes a position nearly vertical, and beats its wings with great intensity. These organs must vibrate all the more rapidly, because the immobility of the body requires a shorter stroke, and therefore the more frequently repeated. The equilibrium of the body is preserved by the alternate up and down strokes of the wings, no inconsiderable force being required to keep its immobility, besides that requisite for neutralizing the weight of the body.
The Humming-Bird is entirely aerial. They pass with the rapidity of an arrow, stop, rest for a few seconds on some small branch, and then suddenly depart with so much rapidity that we cannot trace its flight. They disappear as if by enchantment. Their life is one of feverish excitement. They seem to live more intensely than any other being on our globe. From morning to night they traverse the air in quest of honeyed flowers. They come like a flash of light, assume a vertical position without any support, throw their tail forward, expanding it like a fan, vibrating their wings with such rapidity that they become absolutely invisible, plunging, at the same time, their thread-like tongues to the bottom of some long corolla, and then they have gone as suddenly as they came. They are never known to rest on a branch in order more at their leisure to plunge their tongue into the flower. Their life is too short for this delay; they are in too great haste; they can only stop long enough to beat their wings before each flower for a few seconds, but long enough to reach its bottom and to devour its inhabitants. When we take into consideration how entirely aerial is their life, and the prodigious relative force requisite to enable them to keep suspended in the air during the entire day, almost incessantly, either in rapid motion or accomplishing the most violent vibrations, we can but be amazed at the extraordinary powers of flight and endurance they manifest.
The Humming-Bird enjoys even the most tropical heat, avoids shade, and is easily overcome by cold. Though some travellers speak of having met with these birds in the depths of forests, Saussure discredits their statements, having never found any in such situations. They prefer open flowery fields, meadows, gardens, and shrubbery, delighting to glitter in the sun’s rays, and to mingle with the swarm of resplendent insects with which tropical regions abound, and with the habits of which their own so well accord. Nearly all live in the open sun, only a very few are more or less crepuscular and never to be seen except very early in the morning or in the evening twilight.
Mr. Salvin is of the opinion that Humming-Birds do not remain long on the wing at once, but rest frequently, choosing for that purpose a small dead or leafless twig at the top, or just within the branches of the tree. While in this position they trim their feathers and clean their bill, all the time keeping up an incessant jerking of their wings and tail.
In Mexico, where these birds are very abundant, they are attracted by the blossoms of the Agave americana, and swarm around them like so many beetles. As they fly, they skim over the fields, rifle the flowers, mingling with the bees and the butterflies, and during the seasons of bloom, at certain hours of the day, the fields appear perfectly alive with them. The ear receives unceasingly the whistling sounds of their flight, and their shrill cries, resembling in their sharp accent the clash of weapons. Although the Humming-Bird always migrates at the approach of cold weather, yet it is often to be found at very considerable elevations. The traveller Bourcier met with them on the crater of Pichincha, and M. Saussure obtained specimens of Calothorax lucifer in the Sierra de Cuernavaca, at the height of more than 9,500 feet.
While we must accept as a well-established fact that the Humming-Birds feed on insects, demonstrated long since by naturalists, it is equally true that they are very fond of the nectar of flowers, and that this, to a certain extent, constitutes their nourishment. This is shown by the sustenance which captive Humming-Birds receive from honey and other sweet substances, food to which a purely insectivorous bird could hardly adapt itself.
Notwithstanding their diminutive size the Humming-Birds are notorious for their aggressive disposition. They attack with great fury anything that excites their animosity, and maintain constant warfare with whatever is obnoxious to them, expressly the Sphinxes or Hawk-Moths. Whenever one of these inoffensive moths, two or three times the size of a Humming-Bird, chances to come too early into the garden and encounters one of these birds, he must give way or meet with certain injury. At sight of the insect the bird attacks it with his pointed beak with great fury. The Sphinx, overcome in this unlooked-for attack, beats a retreat, but, soon returning to the attractive flowers, is again and again assaulted by its infuriated enemy. Certain destruction awaits these insects if they do not retire from the field before their delicate wings, lacerated in these attacks, can no longer support them, and they fall to the ground to perish from other enemies.
In other things the Humming-Bird also shows itself all the more impertinent and aggressive that it is small and weak. It takes offence at everything that moves near it. It attacks birds much larger than itself, and is rarely disturbed or molested by those it thus assails. All other birds must make way. It is possible that in some of these attacks it may be influenced by an instinctive prompting of advantages to be gained, as in the case of the spider, in whose nets they are liable to be entangled, and whose webs often seriously incommode them. When a Humming-Bird perceives a spider in the midst of its net, it rarely fails to make an attack, and with such rapidity that one cannot follow the movement, but in the twinkling of an eye the spider has disappeared. This is not only done to small spiders, which doubtless they devour, but also to others too large to be thus eaten.
Not content with thus chastising small enemies, the Humming-Bird also contends with others far more powerful, and which give them a good deal of trouble. They have been known to engage in an unequal contest with the Sparrow-Hawk, yet rarely without coming off the conquerors. In this strife they have the advantage of numbers, their diminutive size, and the rapidity and the irregularity of their own movements. Several unite in these attacks, and, in rushing upon their powerful enemy, they always aim at his eyes. The Hawk soon appreciates his inability to contend with these tormenting little furies, and beats an ignominious retreat.
Advantage is taken of this aggressive disposition of these birds, by the hunter, to capture them. In their combats with one another, or in their rash attacks upon various offensive objects, even upon the person of the snarer himself, they are made prisoners through their own rashness and reckless impetuosity.
In enumerating the prominent characteristics of this remarkable family, we should not omit to refer to the lavish profusion of colors of every tint and shade, excelling in lustre and brilliancy even the costliest gems, with which Nature has adorned their plumage. And not only are nearly all the birds of this group thus decked out with hues of the most dazzling brightness and splendor, when alive and resplendent in the tropical sun, but many also display the most wonderfully varying shades and colors, according to the position in which they are presented to the eye. The sides of the fibres of each feather are of a different color from the surface, and change as seen in a front or an oblique direction, and while living, these birds, by their movements, can cause these feathers to change very suddenly to very different hues. Thus the Selasphorus rufus can change in a twinkling the vivid fire-color of its expanded throat to a light green, and the species known as the Mexican Star (Cynanthus lucifer) changes from a bright crimson to an equally brilliant blue.