Part 30

"Wild ducks and cranes (says Abbé de la Pluche) fly, at the approach of winter, in quest of more favourable climates. They all assemble at a certain day, like swallows and quails. They decamp at the same time, and it is very agreeable to observe their flight. They generally range themselves in a long column like an I, or in two lines united in a point like a > reversed." And thus, as Milton says

"Rang'd in figure, wedge the way."

"The duck or quail that forms the point (adds the Abbé) cuts the air, and facilitates a passage to those that follow: but he is charged with this commission only for a certain time, at the conclusion of which he wheels into the rear, and another takes his post." And thus again, as Milton says,

"----------With mutual wing Easing their flight."

It has been observed of the storks, that for about the space of a fortnight before they pass from one country to another, they constantly resort together, from all the circumjacent parts, to a certain plain, and there forming themselves once every day into a _dou-wanne_, (according to the phrase of the people,) are said to determine the exact time of their departure, and the places of their future abode.

Mr. Biberg, an ingenious naturalist of Sweden, has observed, that "the starling, finding, after the middle of summer, that worms are less plentiful in that country, goes annually into Scania, Germany, and Denmark. The female chaffinches, every winter, about Michaelmas, go in flocks to Holland; but as the males stay in Sweden, the females come back next spring. In the same manner, the female Carolina yellow-hammer, in the month of September, while the rice on which she feeds is laid up in granaries, goes towards the south, and returns in the spring to seek her mate. Our aquatic birds (continues he) are forced by necessity to fly toward the south every autumn, before the water is frozen. Thus we know, that the lakes of Poland and Lithuania are filled with swans and geese every autumn, at which time they go in great flocks, along many rivers, as far as the Euxine Sea. But in the beginning of spring, as soon as the heat of the sun molests them, they return back, and go again to the northern ponds and lakes, in order to lay their eggs. For there, and especially in Lapland, there is a vast abundance of gnats, which afford them excellent nourishment, as all of this kind live in the water before they get their wings."--Mr. Biberg proceeds to enumerate many other birds that migrate to different regions; and he then adds: "By these migrations, birds become useful to many different countries, and are distributed almost over all the globe; and I cannot here forbear expressing my admiration, that all of them exactly observe the times of coming and going, and that they never mistake their way."--_Biberg on the Economy of Nature_, in _Stillingfleet's Misc. Tracts_.

The principal food of the birds of passage, while in Great Britain, is the fruit of the whitethorn, or haws, which hang on our hedges in winter in prodigious plenty; but where they breed, and seem to be most at ease, as in Sweden, &c. there are no haws; nor indeed in many of the countries through which they journey on their way: so that it is evident they change their food in their passage.

The manner in which the birds of passage journey to their southern abodes is supposed to vary, according to the different structure of their bodies, and their power of supporting themselves in the air. The birds with short wings, such as the red-start, black-cap, &c. though they are incapable of such long flights as the swallow, or of flying with such celerity, yet may pass to less distant places, and by slower movements. Swallows and cuckoos may perform their passage in a very short time; but there is for them no necessity for speed, since every day's passage affords them an increase of warmth, and a continuance of food.

Swallows are often observed, in innumerable flocks, on churches, rocks, and trees, previous to their departure hence; and Mr. Collinson proves their return here, perhaps in equal numbers, by two curious relations of undoubted credit; the one communicated to him by Mr. Wright, the master of a ship, and the other by Admiral Sir Charles Wager.--"Returning home, (says Sir Charles,) in the spring of the year, as I came into soundings in our channel, a great flock of swallows came and settled on my rigging; every rope was covered; they hung on one another, like a swarm of bees; the decks and awning were filled with them. They seemed almost famished and spent, and were only feathers and bones; but, being recruited with a night's rest, they took their flight in the morning." This apparent fatigue proves that they must have had a long journey, considering the amazing swiftness of these birds; so that, in all probability, they had crossed the Atlantic Ocean, and were returning from the shores of Senegal, or other parts of Africa.

Naturalists are much divided in their opinion concerning the periodical appearance and disappearance of swallows.--Some assert, that they remove from climate to climate, at those particular seasons when winged insects, their natural food, fail in one country and are plentiful in another, where they likewise find a temperature of air better suited to their constitution. In support of this opinion, we have the testimony of Sir Charles Wager, and of Mr. Adamson, who, in the account of his voyage, informs us, that, about fifty leagues from the coast of Senegal, four swallows settled upon the ship, on the 6th day of October; that these birds were taken; and that he knew them to be the true swallow of Europe, which he conjectures were then returning to the coast of Africa.

But Mr. Daines Barrington, in a curious essay on this subject, has adduced many arguments and facts, to prove that no birds, however strong and swift in their flight, can possibly fly over such large tracts of ocean as has been commonly supposed. He is of opinion, therefore, that the swallows mentioned by Mr. Adamson, instead of being on their passage from Europe, were only fluttering from the Cape de Verde islands to the continent of Africa; a much nearer flight, but to which they seemed to be unequal, as they were obliged, from fatigue, to alight upon the ship, and fall into the hands of the sailors. And Mr. Kalm, another advocate for the torpidity of swallows during the winter, having remarked, however, that he himself had met with them nine hundred and twenty miles from any land; Mr. Barrington endeavours to explain these, and similar facts, by supposing that birds discovered in such situations, instead of attempting to cross large branches of the ocean, have been forcibly driven from some coast by storms, and that they would naturally perch upon the first vessel they could see.

In a word, Mr. Barrington is further of opinion, with some other naturalists, that the swallows do not leave this island at the end of autumn, but that they lie in a torpid state, till the beginning of summer, in the banks of rivers, in the hollows of decayed trees, the recesses of old buildings, the holes of sand-banks, and in similar situations. Among other facts, Mr. Barrington communicated one to Mr. Pennant, that "numbers of swallows have been found in old dry walls, and in sand-hills, near the seat of the late Lord Belhaven, in East Lothian; not once only, but from year to year; and that, when they were exposed to the warmth of a fire, they revived."

These, and other facts of the same kind, are allowed to be incontrovertible; and Mr. Pennant, in particular, infers from them, that "we must divide our belief relative to these two so different opinions, and conclude, that one part of the swallow tribe migrate, and that others have their winter quarters near home."

But there are still more wonderful facts related. Mr. Kalm remarks, that "swallows appear in the Jerseys about the beginning of April; that, on their first arrival, they are wet, because they have just emerged from the sea or lakes, at the bottom of which they had remained, in a torpid state, during the whole winter." Other naturalists have asserted, that swallows pass the winter immersed under the ice, at the bottom of lakes, or beneath the waters of the sea. Olaus Magnus, archbishop of Upsal, seems to have been the first who adopted this opinion. He informs us, that "swallows are found in great clusters at the bottoms of the northern lakes, with mouth to mouth, wing to wing, foot to foot, and that in autumn they creep down the reeds to their subaqueous retreats." In other instances, Mr. Pennant remarks, the good archbishop did not want credulity. But the submersion of the swallows under water does not rest upon his testimony alone. Klein asserts the same; and gives the following account of the manner of their retiring, which he had from some countrymen:

"They asserted, that the swallows sometimes assembled in numbers on a reed, till it broke, and sunk them to the bottom; that their immersion was preceded by a kind of dirge, which lasted more than a quarter of an hour; that others united, laid hold of a straw with their bills, and plunged down in society; that others, by clinging together with their feet, formed a large mass, and in this manner committed themselves to the deep." Bishop Pontoppidan asserts, that clusters of swallows, in their torpid winter state, have sometimes been found by fishermen, among reeds and bushes in lakes; and he charges Mr. Edwards with having, in his Natural History of Birds, groundlessly contradicted this incontestable truth. And Mr. Heerkens, a celebrated Dutch naturalist, in a poem on the birds of Friesland, speaks in positive terms of the torpid state, and submersion, of the swallows:

"Ere winter his somnif'rous power exerts, Six dreary months the swallow-tribes are seen In various haunts conceal'd; in rocks, and caves, And structures rude, by cold benumb'd, asleep; Bill within bill inserted, clust'ring thick: Or solitary some, of mate bereft. But, wonderful to tell! some lie immers'd, Inanimate, beneath the frigid waves, As if a species of the finny kinds."

Mr. Heerkens, after reciting many instances, and producing in his notes many authorities, of swallows having been found in a torpid state, proceeds, in his poem, to describe, very minutely, their ascent out of the water. The drowsy birds appear on the shore, as if unconscious still of life. Some inhale the soft breeze, like one of the finny tribe exiled from its stream. Some begin to adjust their dishevelled wings.--Others, almost revived, essay, with busy bill, to assist their aged companions. All, at length, restored to the unrestrained use of their wings, range, in numerous flights, the aërial way.

Two reasons have, been adduced to prove this supposed submersion of swallows impossible. "In the first place, (says Mr. Smellie,) no land animal can exist so long without some degree of respiration. The otter, the seal, and water fowls of all kinds, when confined under the ice, or entangled in nets, soon perish; yet it is well known, that animals of this kind can remain much longer under water than those who are destitute of that peculiar structure of the heart, which is necessary for any considerable residence beneath that penetrating element."

Mr. John Hunter, in a letter to Mr. Pennant, informs us, "that he had dissected many swallows, but found nothing in them different from other birds, as to the organs of respiration; that all those animals which he had dissected, of the class that sleep during the winter, such as lizards, frogs, &c. had a very different conformation as to those organs; that all those animals, he believes, do breathe in their torpid state, and, as far as his experience reaches, he knows they do; and that, therefore, he esteems it a very wild opinion, that terrestrial animals can remain any long time under water without drowning." Another argument against their submersion arises from the specific gravity of the animals themselves. Of all birds, the swallow tribes are perhaps the lightest. Their plumage, and the comparative smallness of their weight, indicates that Nature destined them to be almost perpetually on the wing, in quest of food. From this specific lightness, the submersion of swallows, and their continuing for months underwater, amount to a physical impossibility. Even water fowls, when they wish to dive, are obliged to rise and plunge with considerable exertion, in order to overcome the resistance of the water. Klein's idea of swallows employing reeds and straws as means of submersion, is rather ludicrous; for these light substances, instead of being proper instruments for assisting them to reach the bottom, would infallibly contribute to support them on the surface, and prevent the very object of their intention. Besides, admitting the possibility of their reaching the bottom of lakes and seas, and supposing they could exist for several months without respiration, what would be the consequence? The whole would soon be devoured by otters, seals, and fishes, of various kinds. Nature is always anxious for the preservation of its species. But if the swallow tribes were destined to remain torpid during the winter months, at the bottom of lakes and seas, she would act in opposition to her own intentions; for, in a season or two, the whole genus would be annihilated.

This reasoning is very ingenious, but, on the other hand, the facts related above are very stubborn; and the celebrated Buffon does not hesitate to yield to the force of such strong and concurrent evidence. He had procured some chimney-swallows, and kept them some time in an icehouse, in order to ascertain whether they were of the torpid kind, and he thus relates the result of his experiments. "None of them fell into the torpid state; the greater part died, and not one of them revived by being moved into the warmth of the sun. Those that had not long suffered the cold of the icehouse, had all their movements, and went out briskly. From these experiments I thought I might conclude, that this species of the swallow was not liable to that state of torpor and insensibility, which supposes, notwithstanding, and very necessarily, the fact of their remaining at the bottom of the water during the winter. Having had recourse, moreover, to the most creditable travellers, I found them agreed as to the passage of swallows over the Mediterranean. And Mr. Adamson has positively assured me, that during the long stay he made in Senegal, he observed the long-tailed swallow, the same with the chimney-swallow we are now speaking of, arrive constantly in Senegal about the time it leaves France, and as constantly leave Senegal in the spring. It cannot, therefore, be doubted, that this species of the swallow passes from Europe into Africa in the autumn, and from Africa to Europe in the spring; of consequence, it neither sleeps nor hides itself in holes, nor plunges into the water on the approach of winter. There is, besides, another well authenticated fact, which comes in proof here, and shews that this swallow is not reduced to a torpid state by cold, which it can bear to a certain degree, (and if that degree is exceeded, it dies,) for if we observe these birds towards the end of the warm season, we shall see them, a little before their departure, flying together in families, the father, the mother, and the young brood. Afterwards several families unite, and form themselves into flocks, more or less numerous in proportion as the time of their departure draws near. At last they go all together, three or four days before the end of September, or about the beginning of October. Still, however, some remain, and do not set off till a week, a fortnight, or three weeks after the rest: and some too there are which do not go at all, but stay and perish under the first rigours of the cold. These swallows that delay their flight, or never undertake it, are such as find their young too weak to follow them; such as have had the misfortune to have their nests destroyed after laying, and have been obliged to rebuild them a second or a third time. They stay for the love of their little ones, and choose rather to endure the rigour of the season, than to abandon their offspring. Thus they remain some time after the rest for the purpose of taking their young with them; and if they are unable to carry them off in the end, they perish with them.

"These facts then plainly demonstrate (concludes Mr. Buffon) that the chimney-swallows pass successively and alternately from our climate to another that is warmer; that they spend their summer here, and their winter there; and of consequence never fall into a state of insensibility. But, on the other hand, what have we to oppose to the precise testimony of those, who, on the approach of winter, have seen these swallows in troops throw themselves into the water; nay, not only this, but have seen them taken out in nests from beneath the ice? What answer shall we make to those who have beheld them in the torpid state, and seen them gradually recover motion and life, when they were brought into the warmth, and moved cautiously towards a fire? I know but of one means of reconciling these facts: we must suppose that the sleeping and travelling swallow are of different species, though the difference, for want of attention, has not been observed."

Thus this great philosopher concurs with Mr. Pennant, in his solution, already mentioned, of the difficulty, by supposing two species--the migrating, and the sleeping swallow. With respect to the principal objects of this wonderful instinct, that teaches such various kinds of the feathered race to migrate to different countries, it is obvious, from what has already been said, that they are governed by their food, temperature of air, and convenient situations for breeding.

We shall now give an account of the CURIOUS METHOD OF BIRD-CATCHING IN THE FARO ISLES.--The manner of bird-catching in the Faro Islands, is exceedingly strange and hazardous. Necessity compels man to wonderful attempts. The cliffs which contain the objects of their search, are often two hundred fathoms in height, and are attempted both from above and below. In the first case, the fowlers provide themselves with a rope eighty or a hundred fathoms in length. The fowler fastening one end about his waist, and between his legs, recommends himself to the protection of the Almighty, and is lowered down by six others, who place a piece of timber on the margin of the rock, to preserve the rope from wearing against the sharp edge. They have, besides, a small line fastened to the body of the adventurer, by which he gives signals, that they may lower or raise him, or shift him from place to place. The last operation is attended with great danger, by the loosening of the stones, which often fall on his head, and would infallibly destroy him, were he not protected by a strong thick cap; but even this is found unequal to save him against the weight of the larger fragments of rock. The dexterity of the fowlers is amazing; they will place their feet against the front of the precipice, and dart themselves some fathoms from it; with a cool eye survey the places where the birds nestle, and again shoot into their haunts. In some places the birds lodge in deep recesses. The fowler will alight there, disengage himself from the rope, fix it to a stone, and at his leisure collect the booty, fasten it to his girdle, and resume his pendulous seat. At times he will again spring from the rock, and in that attitude, with a fowling-net placed on a staff, catch the old birds that are flying to and from their retreats. When he has finished his dreadful employ, he gives a signal to his friends above, who pull him up, and share his hard-earned profit. The feathers are preserved for exportation: the flesh is partly eaten fresh, but the greater part is dried for winter's provision.

The fowling from below has also its share of danger. The party goes on the expedition in a boat; and when it has attained the base of the precipice, one of the most daring, having fastened a rope about his waist, and furnished himself with a long pole, with an iron hook at one end, either climbs or is thrust up by his companions, who place a pole under his breech, to the next footing spot he can reach. He, by means of the rope, brings up one of the boat's crew; the rest are drawn up in the same manner, and each is furnished with his rope and fowling-staff. They then continue their progress upwards in the same manner, till they arrive at the regions of the birds, and wander about the face of the cliff in search of them. They then act in pairs; one fastens himself to the end of his associate's rope, and, in places where the birds have nestled beneath his footing, he permits himself to be lowered down, depending for his security on the strength of his companion, who has to haul him up again; but it sometimes happens that the person above is overpowered by the weight, and both inevitably perish. They fling the fowl into the boat, which attends their motions, and receives the booty. They often pass seven or eight days in this tremendous employ, and lodge in the crannies which they find in the face of the precipice.

We shall close this division of our work with A CURIOUS ACCOUNT OF THE SONG OF BIRDS.--We introduce the subject by the following poetical quotations; which, we have no doubt, will interest every admirer of nature, and nature's God.

Every copse Deep-tangled, tree irregular, and bush Bending with dewy moisture, o'er the heads Of the coy choristers that lodge within, Are prodigal of harmony. _Thomson._

Each bird, Or high in air, or secret in the shade, Rejoicing, warbles wild his grateful hymn. _Mallet._

From branch to branch the smaller birds with song Solace the woods, and spread their painted wings Till even; nor then the solemn nightingale Ceases to warble: in shadiest covert hid, She all the night tunes her soft lays. _Milton._

Again:--

The sweet poet of the vernal groves Melts all the night in strains of am'rous woe. _Armstrong._

Again:--