Fissirostres.
The Fissirostral Passerinæ are characterised by a broad, short bill, flattened horizontally, and slightly hooked; mandibles slightly concave; mouth very wide. They are essentially insectivorous. They comprehend three genera:—1. Swallows (Hirundo). 2. House Martins (Chelidon). 3. Sand Martins (Cotyle).
The Swallows are recognisable by their long pointed wings, forked tail, and excessively short tarsi. The air is the true element of these birds; they fly with a facility, lightness, and rapidity quite inconceivable; indeed, their existence is one eternal flight. They even feed their young on the wing when the latter first begin to fly. Watch them in the air, and they will be seen to rise and fall, tracing the shortest curves, crossing and interlacing each other's course, moderating their pace suddenly when at their utmost speed in order to follow the eccentric course of some winged insect which they have doomed for their food. Such, indeed, is the rapidity of their progress that some of the species have been known to travel at the rate of thirty leagues an hour.
Fig. 240.—Window Swallows (Hirundo rustica, Linn.).
This wonderful power, however, is only developed at the sacrifice of another locomotive faculty, for they are bad walkers. With their short limbs, activity on their feet is impossible; and if by chance they are placed on the ground, with difficulty they rise again on the wing. On the other hand, their sight is excellent—equal to even that of the Eagle or Falcon. According to Spallanzani, who made numerous experiments on the Swallows, the Martin perceives the winged fly passing through the air at the distance of more than a hundred and twenty yards.
Swallows are celebrated for their migratory journeys. In the early days of spring they reach Europe, not in flocks, but as isolated individuals or in pairs. They occupy themselves almost immediately either in repairing their last year's nests, or, if these have been destroyed, in constructing new ones. Among the arrivals are many young birds of the previous year which have not had nests, and yet it is not a little extraordinary that these, after six months' absence, return with unerring certainty to the old dwelling where hatched. This fact has been too often recorded to admit of any doubt on the subject.
The form, structure, and locality of the Swallow's nest vary with the species. The Common Swallows (H. rustica), [Fig. 240], build theirs in the upper angles of the window of some country house, under the eaves of a roof, or on the interior wall of a chimney. A chimney seems an odd place to select for such a purpose; and White of Selborne relates, not without some expressions of wonder at such a choice, that near the middle of May one of these little birds began to form her nest about five or six feet down a chimney adjoining the kitchen fire. Their nests consist of a crust or shell of mud mixed with straw, and lined with fine grass and feathers. Other species, sometimes in vast numbers, establish themselves in the clefts of dead trees. Audubon estimated at the incredible number of eleven thousand the quantity of Swallows which had taken up their dwelling in a sycamore tree (familiarly known there as a button wood) near Louisville, Kentucky, United States. Some Swallows prefer rocks or caverns, and hollow out in steep escarpments a gallery from two to three feet in depth, at the extremity of which they place their nest. Sometimes the nest is formed of twigs torn by the bird from the dead branches of trees, and bound together by a viscous liquid which flows from the bird's mouth.
When, after a month's labour, the Swallows have finished their dwellings, the female deposits from four to six eggs. Incubation commences, and continues from twelve to fifteen days, during which the male bird exhibits intense interest in the proceedings, carrying food continually to his mate, and passing the night in her immediate vicinity, twittering and chirping all day long to cheer the mother at her task. Two or three times in the season they thus raise a family.
From the time when the little ones are hatched the parent birds attend them with all the care their feebleness demands, and often exhibit remarkable proofs of affection. When the young Swallows feel strong enough to try their wings, the old ones tenderly guide them on their first attempts at flight, and teach them how pursuit of insects in the air is successfully performed. Boerhaave quotes an instance where a Swallow, returning from some distant excursion, found the house in which it had built its nest in flames. It did not hesitate an instant to throw itself into the fire in order to save its young.
Swallows generally prefer the proximity of a lake or river, the surface of water being always the rendezvous of crowds of insects, among which they can reap a plentiful harvest. Swallows are extremely sociable; they assemble in large flocks, and appear to be bound together by strong attachment, for they aid each other in trying circumstances.
"I have seen a Swallow," says Dupont de Nemours, "which was unfortunate, and had, I know not how, entangled its foot in a ball of string, one end of which was attached to the roof of the College of the Four Nations; its strength was exhausted, and it hung uttering painful cries at the end of the string, only endeavouring to release itself occasionally by fluttering attempts at flight. All the Swallows between the Tuileries and the Pont Neuf, and perhaps for a much greater distance, were assembled to the number of many thousands, forming a perfect cloud, uttering cries of alarm. All that came flew past, giving a peck of their bill at the fatal string; these blows, being frequently repeated, and always directed at the same spot, were finally successful, for in half an hour the string was cut and the captive set at liberty."
Another fact, related by the great naturalist Linnæus, proves how strong is the spirit of brotherhood with these birds. When the Window Swallows returned in spring to take possession of their nests, a certain number of them were found occupied by Sparrows. One of the more legitimate proprietors, thus despoiled of his property, endeavoured by every possible means to recover possession, but all was unavailing. Under these circumstances the assistance of its companions was demanded. The whole assembly proceeded to besiege the intruder. It resisted, intrenching itself in its fort, and in revenge the ousted Swallows brought mud in their bills, and actually walled up the entrance to the citadel and entombed the interloper in his cell. The truth of this account, which is repeated by many naturalists, has been denied; but Mr. McGillivray, than whom we have no more reliable author, records three well-authenticated similar instances.
The Swallow generally leaves us in the month of September in order to seek a milder climate, and one providing more abundant food in winter. Some time before their departure their cries are incessant, and great agitation is seen in their ranks; they assemble in some elevated place, as if to hold council and deliberate over their journey, and fix the date of their departure; finally, a day is decided on, which when it arrives, all the Swallows of the neighbourhood mass at an appointed place, and after certain evolutions, intended, no doubt, to determine the route, they advance in one mass towards the shores of the Mediterranean, whence they pass into Africa. Although they are of all birds the strongest on the wing, and best adapted for a long journey, they cannot accomplish this without rest if adverse winds should arise. Ships passing are frequently boarded by stragglers which light on the rigging; and both at Gibraltar and Tangiers large flocks are occasionally seen to arrive in a state of great exhaustion. Those stragglers which, through weakness or the duties of maternity, are prevented from joining the great flocks, depart some days later in smaller parties. Occasionally, however, a few individuals seem to remain with us all the year round, contriving to survive the most severe winters, which has given rise to the supposition that the Swallow has the power of hibernating, or of remaining in a state of torpor during the winter, and returning to animation in the spring. This much-controverted point has now been consigned among the mythical legends to which it belongs.
Swallows have in all ages possessed the sympathies of mankind, some of the ancients regarding them as sacred birds; nor are they ungrateful for the good feeling they excite. The services they render in destroying vast quantities of noxious insects, not to speak of their gentle habits, mutual attachment to each other, and the happy presage they bring with them of spring's advent, contribute to make them welcome visitors. Nevertheless there are instances where these proper sentiments yield to the love of destruction—where their innocent confidence is rewarded by death.
Fig. 241.—The Cliff Swallow (Hirundo fulva, Gin.).
Swallows generally have the breast and belly white, and the upper parts of the body black, tinted with a reflected blue or peach colour. There are about sixty species spread over the globe, of which six only are natives of Europe. They are divided into Swallows proper (Hirundo), Martins (Chelidons), Sand Martins (Cotyle), and Swifts (Cypselus). The Martins are larger in size than the true Swallows; have the wings longer, and consequently their powers of flight are greater and their speed more sustained; their claws are more robust and hooked.
The principal species we have already named. It is only necessary to mention the Cliff Swallow ([Fig. 241]), the Chimney Martin, the Bank Martin, and the Alpine Swift (Cypselus alpinus), [Fig. 242].
Fig. 242.—The Alpine Swift (Cypselus melba, Wood).
Among the foreign species the Salangane Swallow ([Fig. 243]) may be mentioned, so famous over the world for its edible nest. This bird inhabits the rocks and caverns of the sea-shore in Sumatra and Java. When building it eats of the plant called fucus, which abounds in these regions; this is metamorphosed in the bird's stomach, and afterwards disgorged, to fabricate the walls of its nest. The fucus thus devoured forms the nutritive substance so eagerly sought after by the Eastern gourmet. The consumption of the nest of the Salangane ([Fig. 244]) in China, in spite of its high price, is very considerable. From the days of Buffon there have been exported from the coast of Cochin China four millions of them annually; and the proprietors of one cavern in the island of Java receive annually fifty thousand florins for rent alone.
Fig. 243.—The Salangane Swallow (Hirundo esculenta, White).
The distinctive features of the Goatsuckers (Caprimulgus) are a short, much-depressed bill; the body small in proportion to the plumage; the neck short; the head large, broad, and depressed; the eyes very large and broad; the feet very small; tarsi partially feathered; toes four, the lower surface broad and flattened, the anterior toes connected by basal membranes; claws moderate, arched, and compressed. The plumage is full, soft, downy, and blended, like the Owl's; the wings have the second and third quills longest; tail long and rounded. Almost all the species have strong bristles along the base of the upper mandible, and some have the feathers of the face radiated, like those of the Owls.
Fig. 244.—Nest of the Salangane Swallow.
The Goatsuckers are solitary birds, living generally in pairs, sleeping during the day, and issuing from their nest with the setting sun, or possibly earlier in gloomy weather, to chase the crepuscular and nocturnal insects on which they feed. They move silently and with great rapidity. Some authors say that when on the wing they keep the mouth open; but this is not supported by facts, and is opposed to reason. The insects they principally devour are moths, dragon-flies, beetles, crickets, cockchafers, and mosquitoes. Their usefulness, therefore, is nearly equal to that of the Swallow. As they get very plump and fat in the autumn, they fall a sacrifice to the gunner, and in their turn are eaten by gourmets greater than themselves. They are migratory birds, travelling only during the night. They are readily distinguished by the bristles at the base of the bill, and by the claws of the middle toe, which is toothed. The object of this toothed appendage has been the subject of speculation. Some writers fond of the marvellous even surmise that it is intended to comb and smooth the head feathers. Mr. Vigors is of opinion that it may be useful as a further power of prehension, citing, in support of his view, the family of the Ardeidæ among the Wading birds, which exhibit an analogous construction in the middle nail.
Through Europe, Asia, Africa, America, and Australia the Goatsuckers are diffused, and naturalists have divided them into several sub-genera, such as Podargus, represented by Podargus humeralis of the Gold River, and Podargus javanensis, the Chabba-wonno of Java, and the Guacharo Bird, Steatornis villot of Humboldt and Bonpland.
The typical species of Caprimulgus is the Night-jar (C. europæus), [Fig. 245]. It is about the size of a Thrush; and Montagu states that he observed on one occasion a flock of eight or ten on the wing together, in the dusk of the evening, skimming over the surface of the ground, after the manner of Swallows, in pursuit of insects. Its nest is of the simplest kind, for it deposits its eggs on the bare ground, or upon a few dry leaves. These eggs, in number only two, are hatched by the female in fourteen days.
The Common Night-jar is chiefly found on furzy commons, wild bushy heaths, and broken hilly ground in the neighbourhood of thickets and woods. During the day it lies concealed in the scrub, issuing forth in the balmy summer evenings to pursue its insect prey on the wing.
On the prairies of North America, especially those intersected by sloughs, dozens of these birds may be seen at the hour of sunset, their swift, powerful, and graceful flight being worthy of the greatest admiration. They are there called Bull Bats, and are often accused by the ignorant of the crime of sucking milk from cows—about as probable as snakes being guilty of the same offence; yet there are hundreds who believe in such impossibilities.
The Night-jar is a bird of evil omen in the estimation of our rural population: such it has been considered since the days of Aristotle, and possibly even further back. The reverse should be the case, for the benefit it produces by clearing the air of noxious insects is incalculable.
The Guacharos are singular birds, which were first described by MM. Humboldt and Bonpland as being found in the interior of a vast Columbian cavern—the Grotto of Caripe. Their hooked bill and general aspect are more robust than the Night-jars, for they more resemble birds of prey. They inhabit in thousands the deep recesses of the caverns of the Cumana Chain, hanging to the walls by their pointed claws. In these caves, which they only leave during the night, they build their nests. Unlike their congeners, they feed only on grain and seeds. The Indians of Caripe enter these sombre domains from time to time, and make raids upon their ranks, for they are deservedly esteemed as great delicacies.
Fig. 245.—The Night-jar (Caprimulgus europæus, Sw.).