Part 18

We must not omit to mention the American SAILOR SWALLOWS (_Progne_), partly because they have frequently been seen in Europe, but more especially as they form the connecting link between the Swallows and the Swifts; they are powerful birds, with long, broad wings, extending beyond the very decidedly forked tail. Their beak is strong, broad at the base, compressed at its sides, much arched, and terminates in a hook; the legs are robust, the tarsi bare, and the toes thicker and more fleshy than those of other Swallows. The plumage is very dense.

THE PURPLE SWALLOW.

The PURPLE SWALLOW (_Progne purpurea_) is seven inches and a half long and fifteen and a half broad; the wing measures about five, and the tail two and a half inches; the centre feather of the latter does not exceed two inches. The female is a trifle smaller and more slender than her mate. The plumage is of a deep blackish blue, shaded with purple; the quills and tail-feathers are blackish brown; the eye dark brown, the beak blackish brown, and the foot purplish black. The head of the female is brownish grey, spotted with black; the upper part of the body is greyer in tint than that of the male, and streaked with black.

This bird is a particular favourite with the Americans, and has been described at great length by many writers. According to Audubon, the Purple Swallows appear in New Orleans about February, and at once come sweeping about the towns or over the streams and rivers. Near the Falls of the Ohio, they are not seen till March, and in Missouri not before the middle of April. In August they leave for more southern countries, assembling like their European brethren upon steeples or high trees, preparatory to starting upon their travels. The flight of this species resembles that of the Roof Swallow, but upon the earth and among the branches of trees its movements are far more easy, and it frequently alights to seek for insects on the ground. Whilst upon the wing, it often bathes and drinks in the same manner as our English Swallows, and like them seizes its prey as it darts through the air. Its disposition is bold and courageous, insomuch that it will frequently chase cats, dogs, Falcons, Cranes, or even Vultures, with great intrepidity.

The nest of the Purple Swallow, which is long and flask-shaped, is formed of dry twigs, grass, leaves, feathers, and other elastic materials, and is either built against a tree or placed in similar situations to those selected by its congeners. The female produces two and sometimes three broods, and lays from four to six purely white eggs; the first family is fully fledged by May, and the second about July. Both parents assist in the work of incubation; the male proves himself a most tender and devoted spouse, and often spends whole hours at the side of his mate, singing to her with great vivacity. Should several pairs brood near the same spot, the utmost harmony prevails among them.

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Pursuant to our intention of laying a _natural_ classification of the Animal Kingdom before our readers, we shall now proceed to describe the SWIFTS, although we are well aware that many modern naturalists consider that they should not be grouped with the Swallows.

The family of the SWIFTS (_Cypseli_) are small or moderate-sized birds, with a long slender body, short neck, broad flat head, and small delicate beak, which is broad at its base, slightly curved, and somewhat compressed at its tip. The gape is uncommonly wide; the wings are narrow and curved like a sabre; the tail is very variously formed, being sometimes long, sometimes short, and more or less deeply incised at its extremity; the feet and toes are stunted, the latter armed with short, powerful, and much curved claws. The plumage is thick and composed of small feathers, it is usually of a dusky hue, but occasionally exhibits considerable metallic lustre. The various members of this family are found throughout all the divisions of our earth, except its most northern portions, and inhabit every situation from the sea-coast to the snow boundary of lofty mountain ranges. From early morning till late in the evening, they may be seen skimming through the air with astonishing rapidity, or soaring to such an elevation as to be almost beyond the reach of our vision. So powerful are their wings that no amount of exertion appears to fatigue them; their pinions, which when extended form a crescent, are wielded with a force and rapidity rivalling the activity of the Humming Birds--they dart with the velocity of an arrow upon their prey, or indulge in every conceivable variety of flight or motion, as they skim through what may certainly be called their native element; even when among the branches of trees, they display considerable agility, but are perfectly helpless upon the ground. All the members of this family are of a restless disposition; they spend but a few hours of the night in repose, and require a very large amount of food to enable them to support their prolonged exertions, so that they consume insects in enormous quantities, seizing them whilst upon the wing.

All such species as inhabit the temperate zone migrate with the utmost regularity as winter approaches, and return to their native haunts with such unfailing precision that the day on which they will re-appear may be accurately prognosticated. Those species inhabiting the interior of Africa never actually migrate, but occupy themselves in flying over the face of the country during the wet season. The work of constructing the nest is commenced as soon as the winter journeyings are over, and is always carried on amidst great excitement; the males chasing and fighting each other most furiously during the whole time, and constantly engaging in pitched battles with the birds whose nests they prefer taking rather than undergo the labour of constructing a home for themselves. Unlike the nests of the Swallows, those built by the Swifts seldom consist of more than a few slight materials laid carelessly together, and cemented with saliva from the builder's beak. The eggs are round and white; the female alone broods, but both parents share in the toil of satisfying their hungry progeny.

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The TREE SWIFTS (_Dendrochelidon_) constitute a group whose various species form a link between the Swallows and the Swifts Proper. These birds are recognisable by their elongate body, long wings, in which the two first quills are of equal length, their long, deeply-forked tail, and the crest with which their head is adorned: their feet resemble those of the Swallow.

THE KLECHO.

The KLECHO (_Dendrochelidon klecho_), so called from the sound of its cry, is about seven inches long; the wing measures six, and the tail three inches. Upon the upper part of the body the plumage is of a brilliant metallic steel-green; the wing-covers have a blueish lustre; the quills are blackish on the inner and blue on the outer web, and the shoulder-feathers white. The belly is white, the rest of the under surface and rump of a beautiful deep grey. The male has a reddish brown and the female a black spot near the eye.

The Tree Swifts differ almost entirely in their mode of life from any other members of their family. Extensive woods and dense forests are their favourite resorts, such being preferred as are in lowland districts; according to Jerdon, the Indian Klecho constantly builds in these localities, flying from thence over the streams or lakes in the vicinity in search of insects on which it subsists. Whilst resting from its labours it usually selects a withered tree for its perch, and amuses itself by expanding and playing with the beautiful crest upon its head. Its flight is excellent, but it climbs awkwardly among the branches. When upon the wing it utters almost incessantly a loud parrot-like scream; when perched its voice is not quite so harsh. We learn from Bernstein that, unlike all other Swifts, the Klecho usually builds at the summit of a tree, upon a branch of about an inch in thickness. Its strange nest, the walls of which are scarcely thicker than parchment, is constructed of bits of bark, feathers, and other similar materials, woven together, and cemented with saliva. The great peculiarity of the nest consists in the fact that it is only just big enough to contain the one large egg laid by the female, and that the walls are far too delicate to bear the weight of the brooding mother; the bird is, therefore, compelled to perch and support herself upon the branch, and merely allow her breast to cover and warm her offspring. The female lays twice in the season; the egg is perfectly oval and of a blueish tint.

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The SALANGANES (_Collocalia_) are a group of Swifts whose edible nests have been famous from time immemorial, but as to whose life and habits little information has been acquired. These birds are distinguished by their small size, long wings, in which the second quill exceeds the rest in length, their forked or slightly incised tail, small but powerful beak, and delicate feet, the exterior toe of which is directed backwards. In all the members of this group the salivary glands are much developed.

THE SALANGANE PROPER.

The SALANGANE PROPER (_Collocalia nidifica_), as we will call the species most extensively met with, is from four to five inches long, and twelve inches broad. Its wing measures about four inches and a half, and its tail two and a quarter. The plumage is of a greyish brown, paler upon the under surface; the quills and tail are blackish, and the vicinity of the eyes marked with white. The feathers of the adult have a slight metallic lustre that is not perceptible in the young. It was formerly supposed that these remarkable birds were only found upon the Sunda Islands, but modern observation has proved that they also inhabit the mountains of Assam, the Neilgherries, Sikkim, and Ceylon. Most contradictory tales have been told by travellers as to the materials of which their famous edible nests are composed.

The earliest account of these nests is met with in Bontius, who tells us that "Large flocks of very small birds of the Swallow kind come down during the breeding season, and settle upon the Chinese coasts, where they swarm over the cliffs that overhang the sea. In these situations they build their strange nests, forming them of fish spawn, which they collect from the shore. These nests are much valued by the natives, who will often pay very large sums of money for them, in order to make them into soup, which is considered a dainty." More modern investigators have been equally inaccurate in their surmises, some pronouncing them to be constructed of the flesh of a kind of snail or worm, or a peculiar species of sea-weed, gathered from the shore. Recent observations upon this interesting point have, however, proved that all these explanations are incorrect, and we learn that these luxuries, in which the Chinese so much delight, are formed of a secretion resembling saliva, drawn from under the bird's own tongue. After a great variety of experiments as to its component parts, Marsden pronounces that the material resembles a mixture of gelatine and white of egg, an opinion in which Bernstein, who is a trustworthy authority on this disputed question, entirely coincides; we will, however, describe the nest of the Salangane before we give our readers the real secret of its construction, as vouched for and described by the last-mentioned naturalist. The Salangane usually builds in such deep and dark cavities that the observation of its proceedings as it fastens its small, thin, gelatinous nest to the rock, is attended with great difficulty. This structure is in shape like the quarter of an egg-shell, divided longitudinally along its entire length. Some of these nests are white, some of a brown colour, and opinion differs considerably as to the reason of this variety; we ourselves believe it to depend on the age of the structure, as we have never seen a brown nest occupied, but other authorities pronounce them to be the work of two distinct species. In the markets the white nests command a very high price, while such as are dark are but little esteemed. The two white eggs laid by the Salangane are deposited at the bottom of this remarkable gelatinous receptacle, without any further preparation for their warmth or comfort.

THE KUSAPPI.

The abode of the KUSAPPI (_Collocalia fuciphaga_) is much more easy of access than that of its congener above described, as it is either placed at the bottom of a hole, or affixed to the naked rock. In shape it resembles that of the Salangane, but its walls are partially composed of stalks of plants, horsehair, and blades of grass, not woven, but cemented together with the aforesaid gelatinous secretion, by which it is also attached to the surface of the cliff. The amount of the mucilaginous substance used varies considerably, some nests being in great measure composed of it, whilst such as are formed of very pliable extraneous materials are made to a certain extent without its aid. Bernstein gives the following account of the process of building the nests of the Kusappi, and has proved the accuracy of his statements by numberless experiments, having even drawn the slimy thread himself from the bird's beak. "Shortly before the breeding season," says Bernstein, "the glands beneath the tongue of these birds become unusually distended, and present the appearance of two large swellings, which diminish considerably in size after the nest is completed. When about to make the foundation of its future abode, the Kusappi presses its tongue against the rock that is to serve for a support, and then, retiring a few paces, draws out a long gummy thread, which dries with great rapidity; this process is repeated, until a crescent-shaped mass is formed, and firmly fastened to the stone. The bird then takes the blades of grass, or stalks of other plants, one after another, from a heap it has already prepared, and cements them together by a similar operation, producing, as it turns its head from side to side, in order to draw out its thread, the undulating lines so frequently seen upon these remarkable structures, and this process is continued until the nest has assumed the necessary dimensions." The Salangane's method of proceeding is essentially similar to that adopted by the Kusappi, but, as we have already said, it builds entirely with the gelatinous threads, without any foreign admixture. We have frequently remarked that such of these birds as are well fed exhibit a much more considerable enlargement of the glands than is observable in those that have only been able to obtain a scanty supply of nourishment. This fact explains the reason why so much difference is constantly noticeable both in the size and beauty of these much-prized nests, millions of which are annually consumed, such as are very clear and delicate often realising fabulous prices. Java is particularly rich in this article of commerce, and Epp thus describes one of the localities in which the nests are most numerously met with:--"The Karang Kallong," he says, "is a huge chalk rock, rising perpendicularly from the sea, by which it is surrounded, and is garrisoned with a force of twenty-five men, whose sole duty is to protect the birds while building. A large tree grows at the edge of the steep, and from this point of view those who venture to look down behold the busy workers swarming beneath, appearing in the distance no larger than bees. The sides of the precipice contain nine caverns, each of which has its name, and can only be entered by a man lowered from above; should the rope break, his death is inevitable, and even if this danger be escaped, the task of finding the entrance to the cavern is attended with great peril, as the foaming waves constantly dash high enough to conceal it from view. The natives who engage in this terrible undertaking fortify themselves for their task by a dose of opium, and offer up a prayer to the Goddess Njaikidul before making the descent." In 1847 no fewer than 2,700 people inhabited the summit of the Karang Kallong, and of these 1,500 men were thus employed. Enormous numbers of nests are exported annually from this place to China, and are sold at very high prices; but those who thus risk their lives to obtain the expensive luxury are but poorly remunerated. We are but little acquainted with the habits of these birds, except that they fly with great rapidity, and constantly frequent the sea-shore.

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The PRICKLY-TAILED SWIFTS (_Acanthylis_) are distinguished from other members of their family by the very peculiar construction of their tail-feathers, the shafts of which extend beyond the web; the plumage is also thicker, and the tarsi longer and more powerful than in most other species.

THE WHITE-THROATED PRICKLY-TAILED SWIFT.

The WHITE-THROATED PRICKLY-TAILED SWIFT (_Acanthylis caudacuta_) is about eight inches and a half long, and twenty broad; the wing measures eight and the tail two inches. The head, upper tail-covers, sides of the wings, quills, and tail are pale black, with a metallic greenish blue gloss; the back and shoulder-feathers are whitish brown, the breast and nape white. The under side is blackish brown, the lower wing-covers and a streak on the side of the head are white, more or less intermixed with glossy, blackish blue feathers. The inner web of the secondary quills is also white; the beak is black, the foot lead-colour, and the eye deep brown.

We learn from Jerdon that this species is found in the south-eastern provinces of the Himalaya, Nepaul, Sikkim, and Bhotan, and that its flight is extraordinarily light and rapid. The breeding settlements are generally at a considerable height in the mountains, but always below the snow boundary. The strange prickly tail appears to be employed to assist the bird while climbing. Further particulars as to its habits and mode of life are entirely wanting.

THE DWARF SWIFT.

The DWARF SWIFT (_Cypselus parvus_) is a small species found in some parts of Central Africa, where it usually frequents the forests or woodland districts. Its length does not exceed five inches and a half, and its breadth is eleven inches. The plumage is almost entirely dark grey, lightest upon the throat; the wings are of a brownish hue. In its general habits the Dwarf Swift resembles its congeners, but the structure of its nest is so remarkable as to merit a minute description. Brehm tells us that upon one occasion, whilst travelling in the vicinity of the Blue River, he was attracted by cries uttered by one of these birds as it flew backwards and forwards near a lofty palm whose branches towered above the surrounding trees. On going nearer the spot, he observed that the Swift kept disappearing, as it were, within one of the large, fan-like leaves, against the glossy green of which several white objects were distinctly visible. Thinking this circumstance somewhat extraordinary, he climbed the tree, and found, to his no small astonishment, that the said green leaf was the nest, and the white objects, the eggs, of the noisy bird. We should, perhaps, be more accurate if we said that the leaf formed the outer part of the nest, the actual chamber for the young being composed of cotton wool and feathers, fastened together with saliva, and in shape resembling a round spoon: the interior did not exceed two inches and a half in diameter. Guided by a most wonderful instinct, this little builder seems perfectly aware of the danger to which its aërial abode is exposed from a strong wind, and takes the very safe precaution of gumming with her tenacious spittle not only the nest and eggs, but the nestlings also, firmly to the leaf. Another peculiarity in the domestic arrangements of this species is that the two white eggs that compose a brood are fastened end upwards, in the very limited bed prepared for their reception.

THE PALM-TREE SWIFT.

The PALM-TREE SWIFT (_Cypselus palmarum_) constructs its nest in a very similar manner to the Dwarf Swift.

THE STEEPLE SWIFT.

The STEEPLE SWIFT (_Cypselus apus_) is from six to seven inches long and fifteen and a half broad; its wing measures six and a half, and tail three inches. Its plumage is of a blackish brown, with the exception of the throat, which is white; the eyes are brown, the beak and feet black.

The Steeple Swifts are met with throughout the southern countries of Europe, in Central Asia, and over the entire continent of Africa. They appear in Europe with the utmost regularity on the first or second of May, and usually leave about the first of August. Such of them as are seen after that period find their way to us from more northern countries, having been left behind by their companions. The migrations of these birds are undertaken in large flocks and are usually commenced at midnight. Like all its congeners, the Steeple Swift is extremely restless, active, and lively in disposition, but differs considerably in its habits from all other members of its family. The air is its home, and almost its entire life is passed upon the wing. From early morning it may be seen, either sailing through the sky at a considerable height, or skimming along in its tortuous course as it pursues its insect prey. In general, however, it is only towards evening, or if the sky be wet or cloudy, that it approaches the surface of the earth. Such of these birds as inhabit the Canary Islands are an exception to this rule, for, according to Bolle, they invariably seek the shelter of their holes for a couple of hours during the forenoon. So extremely awkward are the movements of this species when upon the ground, that it is commonly supposed to be unable to rise if it should chance to alight on _terra firma_. This idea is, however, incorrect, for with the aid of its wings it is enabled to make a violent spring, and thus recommence its flight. The feet of the Swift are almost useless for walking; they are, however, invaluable assistants to the bird when climbing, and the sharp claws with which they are armed are most formidable weapons of defence against its adversaries. The sight and hearing of the Steeple Swifts is excellent, but in every other respect they are far below their congeners, with whom they live in a constant state of warfare; even towards their own species they exhibit the same violent and revengeful disposition, falling upon and clawing each other with such violence as often to tear the flesh from their opponent's breast. We ourselves have seen the males become so excited in these encounters, as to permit us to approach and seize them with our hands, and Naumann mentions having observed one of these birds dart like a Falcon upon a Sparrow quietly picking up worms in a field, and attack it with such fierceness that the terrified little creature sought refuge between the feet of a man who was standing near the spot.