Immediately after our summer visitants take their departure for the more temperate climates of the south, those of winter, to avoid the more cold and icy regions of the north, arrive in Britain. It is some what surprising that birds of passage, although it may seem much against the facility of their migra tion, and which is analogous to the swimming of fish against the stream, always delight in steering their course against the wind, if not too strong for their flight. Those of summer return to hatch on the same grounds and spot on which they themselves were hatched, while the parents frequently reoccupy their former nests, and those of winter invariably take possession of the same fields and woods which they left, previous to the commencement of our spring. Other particulars will come to be mentioned, when we treat separately, of our most noted birds of pas sage ; and then we shall also produce a few speci mens of the opinions and testimonies of both the writers, for and against submersion and migration.
The most early harbinger of spring, among our birds of passage, is the Swallow. He appears in April lc before the Cuckoo. Upon their arrival, the swal lows first attract our notice, when skimming along some village green, or adjacent pool ; they then seem in good case, their feathers unruffled, and in no re spect the worse of a long flight. Of this genus, we have four species that visit this island. The chimney swallow (hirundo rtutica,) the house martin (hirun.
do urbica,) the sand martin (hirundo riparia,) and the swift or black martin (hirundo apus,) which does not appear till May. In this order they arrive, one after another, the chimney swallow preceding the others by several days. This is the bird that has given rise to so much controversy concerning its winter retreat ; some naturalists, however, take in the whole tribe, indefinitely, in this dispute. Olaus Magnus, Etmuller, Biberg, Forster, Barrington, and even Linnaeus, seem to favour the opinion of the submersion, and after resuscitation of the swallow.* We shall quote a few of the most striking, from the many authorities given in support of this wild and supposed process in natural history.
" Mr Peter Brown, a Norwegian, and ingenious painter, informs me, that, from the age of six to seven teen, whilst he was at school near Sheen, N. lat. 59°, lie with his companions hath constantly found swal lows in numbers torpid under the ice, which covered bogs, and that they have often revived, upon being brought into a warm room." " Mr ::tepliens, A. S. S. informs me, that when he was fourteen years of age, a pond of his father's (who was vicar of Shrivenham in Berkshire) was cleaned during the month of February ; that he picked up himself a cluster of three or four swallows (or mar tins,) which were caked together in the mud ; that the birds were carried into the kitchen, on which they soon flew about the room in the presence of his fa ther, mother, and others, particularly the reverend Dr Pye." -I " Dr \Vallerius, the celebrated Swedish chemist, wrote in 1748, Sept. the 6th. O. S. to the late Mr Klein, secretary to the city of Dantzick, " That be has seen more than once swalloWs assembling on a reed, till they were all immersed, and went to the bottom, this being preceded by a dirge of a quarter of an hour's length. t He attests likewise, that lichad seen a swallow, caught during winter, out of a lake, with a net, drawn as is common in northern countries, under the ice ; this bird was brought into a warm room, revived, fluttered about, and soon after died.".
"I can reckon myself (Forster) among the eye wit nesses of this paradoxon of natural history. In the year 1735, being a little boy, I saw several swallows, brought in winter, by fishermen•from the river Vistula, to my father's house, where two of thern'were brought into .a warm room, revived, and flew about. I saw them several times settling on the warm stove (which the northern nations have in their rooms,) and I re collect well, that the same forenoon they died, and I had them when dead in my hand." In the same style,innumerable affidavits from North America, and other parts of the world, have found their way-, into our newspapers, journals, and maga zines. The Statistical Account of Scotland furnishes us with a specimen, somewhat more circumstantial, but of the same kind with the foregoing, and from being nearer home we shall with it close our proofs 1 -for this submerging system. § " We have no un common migratory birds ; and it is doubtful whether all birds, usually reckoned of this class, do really belong to it. The ground of this doubt well ap pears, from the following observations respecting the swallow. Owing to a hint given to me by a neighbour, I have been for some seasons pretty at tentive to the first appearance of this bird, but not accurate enough to mark the dates, till last spring, when on the 2d of May 1793, I saw them for the first time, pretty early in the morning, in consider able numbers on the loch about eighteen yards from the bottom of the garden,) from which they seemed to be just then in the process of emerging, though, as there was some rippling in the water, it was dif ficult to discern the breaking of the surface, but the observer is positive, they just then arose from the lake, and therefore must have lodged or lain some how at the bottom, since the time of their disappear ing last year. The weather all day continued as it
began in the morning, moderate with an easy breeze from S. W. and the swallows sometimes in bodies, sometimes in detachments, enjoyed themselves, in skimming along the surface, or soaring aloft in the air, or fluttering about the shores, but went very little way off the water till evening, when they collected over the lake, and disappeared within observation. With anxious expectation, they were looked for next morning, and all day through, but no appear ance of them, nor for several days following ; and therefore there can be no doubt of their descending into their lodgings at the bottom • having from that day's experiment, felt or judged the air not sufficient ly encouraging for them to live in. Nor were they seen till the I 1th of May, when they were again observed in the process of emerging from the lake, and continued playing their gambols, and fluttering about the shores of it, until evening, when they dis appeared as formerly, and were seen no more till the evening of the 2Ist of May, when the manner of their disappearing was exactly the same as before mentioned. The last experiment succeeded ; they felt, it should seem, the temperature of the air en couraging, and in a few days began to prepare their summer dwellings." It 'is an unpleasant task to express our doubts, respecting the accuracy and truth of these seeming ly well attested statements ; our readers, however, can give such degree of credit to them as they think they may upon the whole deserve. For our part, we can hold them in no other light than we do the certificates obtained and annexed to the advertising bills of quacks and mountebanks, enumerating the various cases of persons restored to health, by their never-failing medicines. We at the same time admit, that natural history ought not to be studied from conjectures and opinions, but from a historyond col leciion of well known facts. But here where the fences of probability, nay of the laws of nature, are broken down, to give way for a wild hypothesis, and groundless system, we must pause, and have at last recourse to unbelief. But we shall now proceed to offer our reasons, for doubting the correctness of the preceding narratives. The specific levity of a swal low must prevent it from being able to descend to the bottom of a rapid river. No bird could continue for six months under water, without suffocation or corruption. That celebrated anatomist and natur alist, the late John Hunter, tells us, "That he had dissected many swallows, but found nothing in them different from other birds, as to the organs of respi ration," and consequently draws this conclusion, " that they could not remain for any time under water, without being drowned." It is an iticontes tible fact, that swallows do not moult in this country, and if they hibernate under water, it is simply im possible that they can undergo that operation, or at least acquire new feathers there. We may therefore ask, where do they moult ? The ingenious and in quisitive Reaumur says, that he was often promised, from several of his correspondents, ocular demonstra tion, of bundles of swallows to be found under the ice, or that might at any time be discovered torpid in old buildings, Ste. but that none of these gentle men ever kept their words with him. We have also holy writ to confirm us in the belief of the migration of the swallow, " yea the stork in the heaven know.. eth her appointed times, and the turtle, and the crane, and the swallow, observe the time of their coming." (Jeremiah chap. viii. v. 7.) From all these consider ations, we infer, that the whole of the swallow genus are birds of passage, and that they do not remain torpid with us during the winter either above or under water, or in any state whatever. That seme in holes and bores may be found dead, or others drowned, we shall not dispute ; nor shall we pretend absolutely to determine, to what countries they go after leaving us. We are, however, rather inclined to imagine, with Willoughby and Buffon, that they winter hi Africa ; an opinion which is much strength ened by the following observations of Adanson when at Senegal : " (February) The hut where I lodged was large and commodious, but as dark as a subter raneous cavern, even at noon day, because it had no other opening but a door pierced at each end. Here I must observe, that a great number of our European swallows resorted hither every evening, and passed the night upon the rafters ; for as I have elsewhere mentioned, they do not build nests in this country, but only come to spend the winter." Voyage to Sene gal.