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, tha-t, 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, of 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 cringing 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 Fries-land, 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."