CHAPTER X.

_NIGHT-JARS, SWIFTS, AND HUMMING-BIRDS._

NIGHT-JARS.

It is probable that the NIGHT-JARS are the nearest allies of the Owls. As pointed out in the last chapter, although the latter have acquired the habits of the Hawk and Eagle Tribe, they are not really connected with that group by descent.

Soberly clad, so as to be in complete harmony with its surroundings, with large eyes, huge mouth, and peculiarly short beak, beset with long bristles, the night-jar may be distinguished at once from all other British birds. By day it hides, squatting close to the ground, or perched on the thick branch of a tree; but when on the latter, it sits along and not across the bough, like other birds, the complete harmony between its plumage and the bark rendering it as invisible as when on the ground.

Not until the spring has far advanced does this bird leave its winter resort in Africa for Europe, making its presence known by its conspicuous habit of hunting its food (which consists of moths and beetles) after twilight has fallen. Later, its extraordinary churring note is heard--a note which has been likened to the noise made by a spinning-wheel, and so powerful as to be audible half a mile off. This note is made while on the ground: on the wing, while toying with its mate, another equally peculiar sound is made, which has been likened to the noise made by swinging a whip-thong through the air.

No nest is made by this bird; but the eggs, two in number and beautifully marked, are laid on the bare ground. The young are covered with down, and remain in the nest for some time.

Another very remarkable feature is the fact that the claw of the middle toe has its inner edge curiously serrated, forming a sort of comb, the function of which is unknown. This comb-like claw occurs also in some few other birds--bitterns, for instance.

A very remarkable kind is the PENNANT-WINGED NIGHT-JAR, in which one of the quill-feathers in each wing is produced into a "pennant" of some 17 inches in length. The shaft of the feather is bare for the greater part of its length, and terminates in a feathery blade. It is an Abyssinian species about which not much is known.

Some of the night-jars, as the New World NIGHT-HAWK and the Old World EARED NIGHT-JARS, are particularly owl-like, a resemblance imparted by long "ear-like" tufts of feathers which rise from the back of the head. Others, as the MORE-PORK of the Tasmanian colonist, or the FROG-MOUTH, as it is called in Australia, are remarkable for the huge size of the mouth, bounded, as it appears to be, by huge lips, represented by the short, round-edged beak.

Very nearly related to the night-jars is the OIL-BIRD of South America, which lives in caves in Trinidad, Ecuador, and Peru, where it builds a nest which has been likened in appearance to a huge cheese, and in which are laid from two to four white eggs. Like the night-jars, these birds feed by night, emerging from their gloomy retreats at twilight with much noise and in great numbers. Their food, however, is entirely of a vegetable nature, consisting of oily nuts or fruits.

The young, soon after they are hatched, become perfect masses of fat, and on this account are much in demand by the Indians, who make a special business of killing them and extracting the oil.

SWIFTS.

In general appearance SWIFTS bear a strong superficial resemblance to Swallows; in reality they are related, not to those harbingers of spring, but to the Night-jars on the one hand and the Humming-birds on the other.

The COMMON SWIFT arrives in England during the early part of May, and stays till the end of August, or sometimes till September has half run its course. Black in colour, relieved only by a white throat, it has little in the sense of beauty to recommend it; nevertheless, there are probably few who do not cherish tender feelings towards this bird. The swift has great buoyancy of spirits, as is manifested by the wild, exuberant bursts of screaming to which it gives voice as it rushes in small parties down the lanes or along the less-frequented thoroughfares of towns as morning breaks or evening falls, and occasionally throughout the day. The greater part of its life is spent upon the wing (indeed, it appears to rest only when incubating or sleeping), and of all the smaller birds it is the most graceful in flight, turning and twisting in fairy mazes high in the heavens for hours at a time.

The swift chooses for its nesting-place the eaves of houses and holes in church towers, and occasionally a crevice in the face of a quarry. The nest is formed of bits of straw, dry grass, and a few feathers, glued together by a secretion of the salivary glands into a compact crust; in this the bird deposits from two to four white eggs. The young, which are hatched naked and blind, never develop down-feathers, but soon become more or less imperfectly clothed in a mass of tiny spines, representing the budding feathers; these give the bird somewhat the appearance of a young hedgehog.

In adaptation to its remarkable powers of flight, the wing has undergone considerable modification in form, so that it differs from that of all other birds. On the other hand, the legs, being so little required, have diminished considerably, and are remarkable for their smallness--a fact which hampers the bird considerably, should it happen to alight on level ground, for, owing to the great length of the wings, it can arise only with considerable difficulty.

Nearly allied to the common swift is SALVIN'S SWIFT, remarkable on account of its nest, which has been described by Dr. Sharpe as the most wonderful in the world. About 2 feet long and 6 inches in diameter, it looks rather like the sleeve of an old coat than a nest. It is made entirely of the downy seeds of plants, which, floating through the air after the fashion of such seeds, are caught by the birds when on the wing, and, partly felted and partly glued by the salivary secretion, are woven slowly into the characteristic woolly domicile. The site and manner of fixation of the nest are scarcely less wonderful, for it is suspended from the flat surface of some projecting piece of rock on the face of a cliff, and is thus almost inaccessible; yet, as if to make assurance doubly sure, two entrances are made, one at the bottom, which is really blind, and one at the top, near its foundation, if we may call it so, which leads into the nursery.

Still more swallow-like in general appearance are the diminutive EDIBLE SWIFTS, so called, not on account of the palatability of the birds themselves, but of their nests, which are in great demand by the wealthy Chinese for conversion into birds'-nest soup. It has already been remarked that the salivary glands are unusually active in the swifts, their secretion bearing a very important part in the construction of the nest, and serving as a kind of cement. It is, therefore, not surprising that in some members of the group we find this secretion playing a still more prominent part, forming, at least in one species, the entire material of the nest. "With these nests," writes Dr. Sharpe, "a large trade is done with China from many of the Malayan Islands, over 3,500,000 nests having been known to be exported in a single year from Borneo to the latter country.... In Borneo and other places the caves in which the swiftlets build are leased to the collectors for a considerable sum; but it is only the white nests, made of the pure secretion, which are of any real value. The nests of those species which mix into their nests grass or feathers are not appreciated as an article of commerce."

Colonel Legge gives some extremely interesting particulars concerning the nesting habits of these birds in Ceylon. "It is noteworthy," he writes, "that the partially fledged young--which were procured on this occasion for me, and which I kept for the night--scrambled out on to the exterior of the nest, and slept in an upright position, with the bill pointing straight up. This is evidently the normal mode of roosting resorted to by this species. The interior of this cave, with its numbers of active tenants, presented a singular appearance. The bottom was filled with a vast deposit of liquid guano, reaching, I was informed, to a depth of 30 feet, and composed of droppings, old nests, and dead young fallen from above, the whole mingled into a loathsome mass, with water lodged in the crevices, and causing an awful stench, which would have been intolerable for a moment even, had not the hundreds of frightened little birds, as they screamed and whirred in and out of the gloomy cave with a hum like a storm in a ship's rigging, powerfully excited my interest, and produced a long examination of the colony. This guano-deposit is a source of considerable profit to the estate, the hospitable manager of which informed us that he had manured 100 acres of coffee with it during that season."

HUMMING-BIRDS.

It is generally admitted that HUMMING-BIRDS are nearly related to Swifts, with which, however, they stand in the strongest possible contrast in the matter of plumage--the latter being always inconspicuously coloured, whilst the former are for the most part clad in vestments so gorgeous as to render it extremely difficult to describe them in sober language. Moreover, so great is the wealth of species--some hundreds in number--and so varied are the form and coloration, and so closely do the various types pass one into the other, that their classification is a matter of extreme difficulty.

Confined to the American Continent and certain islands adjacent thereto, humming-birds range from Canada to Tierra del Fuego in a horizontal direction, and rise vertically in the mountain-range of Chimborazo to a height of 16,000 feet above the sea-level--"dwelling," as Professor Newton describes it, "in a world of almost constant hail, sleet, and rain, and feeding on the insects which resort to the indigenous flowering plants."

Humming-birds surpass all others in the wondrous beauty of their plumage, which depends not so much on colour as metallic lustre reflecting all the hues of the most precious stones--amethyst, ruby, sapphire, emerald, and topaz gleaming and sparkling from their bodies with a fire and intensity truly marvellous. "In some cases," as Professor Newton aptly describes it, "this radiance beams from the brow, in some it glows from the throat, in others it shines from the tail-coverts, in others it sparkles from the tips of elongated feathers that crest the head or surround the neck as with a frill, while again in others it may appear as a luminous streak across the cheek.... The feathers that cover the upper parts of the body very frequently have a metallic lustre of golden green, which in other birds would be thought sufficiently beautiful, but in the [humming-birds] its sheen is overspread by the almost dazzling splendour that radiates from the spots where Nature's lapidary has set her jewels."

Besides this brilliancy of colour and variety in form--variety due to the development of these crests and frills, or to the forking and elongation of the tail-feathers--still further changes are brought about by the modification of the bill, which may be produced into a long straight style, longer than the body of the bird, or turned up like that of the avocet or down like that of the curlew. These changes are adaptations to the bird's methods of feeding, some seeking their food from the long tubular corollas of flowers, and requiring, therefore, very elongated beaks, others from more open and easily accessible flowers, whilst others hunt among leaves, especially the under-surfaces, the quarry consisting mainly of insects attracted by the honey secreted by the flowers, or those living on the leaves. Not only the beak but the tongue also has undergone great modification in this group, its outer sheath curling up on each side into a thin scroll, so as to form a pair of tubes, the exact use of which is unknown. The wings, like those of the swift, have undergone a certain amount of change in the relative proportion of the several regions, and in the form and number of the quill-feathers, whilst the legs have become considerably reduced in size. In some species each leg is surrounded by a little tuft of down, which may be black, brown, or snow-white in colour. In size these birds vary from 8 inches to scarcely more than 3 inches.

"The beautiful nests of humming-birds," writes Professor Newton, "than which the fairies could not have conceived more delicate ... will be found on examination to be very solidly and tenaciously built, though the materials are generally of the slightest--cotton-wool, or some vegetable down, and spiders' webs. They vary greatly in form and ornamentation--for it would seem that the portions of lichen which frequently bestud them are affixed to their exterior with that object, though probably concealment was the original intention. They are mostly cup-shaped; and the singular fact is on record, that in one instance, as the young grew, the walls were heightened by the parents, until at last the nest was more than twice as big as when the eggs were laid and hatched."

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