What becomes of our swallows in the winter? They migrate, you reply, to a warmer parallel. That is true, no doubt; though there have not been wanting naturalists of respectable name who have maintained that none of them ever leave the country. No doubt, however, they do migrate; but is this true of the entire body, or only of a portion? That the whole hirundinal population—swifts, swallows, martins, and bank-martins—disappear from view, every one knows; for who ever saw any of the tribe wheeling and traversing through the sky in the frosts of January or February? But so do the Bats and the Butterflies. Now, the Bats hybernate with us, concealing themselves in crevices, caves, hollow trees, unused buildings, and similar places; so do the house-flies; so do the butterflies, some species at least, and many other insects. Do the Swallows hybernate? That they do is a very old opinion; and those homely but wide-spread rhymes that record so many accepted facts in popular natural history, record this as a fact. Our rustic children sing—

Local variations—what we may call lectiones variÆ—exist; for example, in the south-east of our island, the third line runs,

In the north of Europe an opinion has long prevailed that the Swallows not only hybernate in a state of torpidity, but, like the frogs and toads, retire to the bottoms of pools to spend that dreary season. In Berger's "Calendar of Flora," published in the Amoenitates AcademicÆ, vol. iv., he puts down as the phenomenon proper to the 22d of September, "Hirundo submergitur," talking, as Gilbert White remarks, as familiarly of the Swallows going under water, as he would of his poultry going to roost at sunset. Klein, and even LinnÆus himself, adopted this strange opinion, which was considered to rest upon good testimony, and that not only of the illiterate and unobservant. Etmuller, who was Professor of Anatomy and Botany at Leipsig in the middle of the seventeenth century, says, "I remember to have found more than a bushel would hold of Swallows closely clustered among the reeds of a fish-pond under the ice, all of them to appearance dead, but with the heart still pulsating." And Derham, the acute author of "Physico-theology," citing this statement, adds, "We had at a meeting of the Royal Society, February 12, 1713, a further confirmation of Swallows retiring under water in the winter from Dr Colas, a person very curious in these matters, who, speaking of their way of fishing in the northern parts by breaking holes and drawing their nets under the ice, saith, that he saw sixteen Swallows so drawn out of the Lake of Lamrodt, and about thirty out of the king's great pond in Rosneilen; and that at Schlehitten, near a house of the Earl of Dohna, he saw two Swallows just come out of the waters, that could, scarcely stand, being very wet and weak, with their wings hanging on the ground; and that he observed the Swallows to be often weak for some days after their appearance."[113]

The Academy of Upsal received the winter submersion of the Swallows as an undoubted fact, and even Cuvier admits as "well authenticated, that they fall into a lethargic state during winter, and even that they pass that season at the bottom of marshy waters."[114] One would think that a zoological statement which LinnÆus and Cuvier accepted, must be fact; yet it remains utterly improbable. In Germany, a reward of an equal weight in silver was publicly offered to any one who should produce Swallows found under water, but we are assured that no one was found to claim the money.

We may safely dismiss the notion of submersion till better authenticated; but that of torpidity is still open to examination. Statements to the effect that quantities of Swallows in a death-like condition have been found in hollow trees, holes in cliffs, banks, &c., are even more common than those of their submersion; and they seem to obtain credence in all the temperate or cold regions where the Swallows are found. It is hard to think that a persuasion so widely diffused can be wholly groundless.

Peter Collinson, the friend and correspondent of LinnÆus, communicated to the Royal Society the following statement by M. Achard:—"In the latter end of March I took my passage down the Rhine to Rotterdam. A little below Basel, the south bank of the river was very high and steep, of a sandy soil, sixty or eighty feet above the water.

"I was surprised at seeing, near the top of the cliff, some boys tied to ropes, hanging down doing something. The singularity of these adventurous boys, and the business they so daringly attempted, made us stop our navigation, to inquire into the meaning of it. The waterman told us they were reaching the holes in the cliffs for Swallows or Martins, which took refuge in them, and remained there all the winter, until warm weather, and then they came abroad.

"The boys being let down by their comrades to the holes, put in a long rammer, with a screw at the end, such as is used to unload guns, and, twisting it about, drew out the birds. For a trifle I procured some of them. When I first had them, they seemed stiff and lifeless; I put one of them in my bosom, between my skin and shirt, and laid another on a board, the sun shining full and warm upon it; and one or two of my companions did the like. That in my bosom revived in about a quarter of an hour; feeling it move, I took it out to look at it; but perceiving it not sufficiently come to itself, I put it in again; in about another quarter, feeling it flutter pretty briskly, I took it out, and admired it. Being now perfectly recovered, before I was aware, it took its flight; the covering of the boat prevented me from seeing where it went. The bird on the board, though exposed to a full sun, yet, I presume from a chilliness of the air, did not revive so as to be able to fly."[115]

On this account I may observe that Collinson would hardly have been the medium of this communication, unless he had been satisfied of the probity of his correspondent. The time was "the latter end of March," a fortnight at least before the arrival of the Sand Martin—the earliest of our migrants; and the whole enterprise of the boys, and the familiarity of the waterman with the circumstance, as well as their assertions, shew that they, at least, had no doubt about this being a case of hybernation. Yet the repeated exploration of the Sand Martin's burrows in this country, in winter, has produced no birds.

White of Selborne, who was very much interested in the solution of this question, mentions two instances—both, however, on hearsay evidence. A clergyman assured him that, when he was a boy, some workmen, in pulling down the battlements of a tower, early in spring, found two or three Swifts among the rubbish, which appeared dead, but revived in the warmth. The other account was that of the fall of a portion of the cliff near Brighton in winter, when many persons found Swallows among the rubbish; but here even White's informant did not see the birds, but was merely told of them.[116]

Bishop Stanley, in his "Familiar History of Birds," has collected some stories which appear circumstantial enough, if we could be quite sure they were authentic; on which point the good bishop seems to give the weight of his own character, since he observes that they are "cases which have come to our knowledge, on the most respectable authority."

"On the 16th of November 1826, a gentleman residing near Loch Awe, in Scotland, having occasion to examine an out-house, used as a cart-shed, saw an unusual appearance upon one of the rafters which crossed and supported the thatched roof. Upon mounting a ladder, he found to his astonishment that this was a group of Chimney-swallows (Hirundo rustica) which had taken up their winter quarters in this exposed situation. The group consisted of five, completely torpid: and none of the tribe to which they belonged had been seen for five or six weeks previously: he took them in his hand, as they lay closely and coldly huddled together, and conveyed them to his house, in order to exhibit them as objects of curiosity to the other members of his family. For some time they remained to all appearance lifeless; but the temperature of the apartment into which they were carried being considerably raised by a good turf fire, they gradually evinced symptoms of reanimation; and in less than a quarter of an hour, finding that they were rather rudely handled, all of them recovered, so as to fly impatiently round the room, in search of some opening by which they might escape. The window was thrown up, and they soon found their way into the fields, and were never seen again. A similar circumstance, though, from the place of its discovery it must refer probably to Sand Martins, was related by a gentleman who found two Swallows in a sand-bank at Newton, near Stirling, quite dormant.

"Again, about half-a-dozen Swallows were found a few years ago, in a torpid state, in the trunk of a hollow tree, by a countryman, who brought them to a respectable person, by whom they were deposited in a desk, where they remained forgotten till the following spring, when, one morning, on hearing a noise, he opened the desk, and found one of them fluttering about: the others also began to shew signs of life, and upon being placed out of doors in the sun, speedily arranged their plumage, took wing, and disappeared.

"On the 2d of November 1829, at Loch Ransa, in the island of Arran, a man, while digging in a place where a pond had been lately drained off, discovered two Swallows in a state of torpor; on placing them near the fire, they recovered. One unfortunately escaped, but the other was kept by the man, for the purpose of shewing it to some scientific persons."

In North America there is a curious species of Swift, (Acanthylis pelasgia,) which associates in immense flocks to roost in chimneys and hollow trees. It is the popular belief that these birds spend the winter in a torpid condition in their roosting trees. Williams, in his "History of Vermont," speaks of a large hollow elm which had been for many years appropriated to this purpose. A farmer resident close to the tree was persuaded that it was the winter dwelling-place of the Swifts, and avoided felling it on that account. About the 1st of May, he always saw them come out of it in large numbers, about the middle of the day, and in a short time return. Then, as the weather grew warmer, they came forth in increased multitudes in the morning, and did not return till night. A similar account was given of another tree: the first appearance of the Swifts in spring was always their emergence from its hollow trunk, and their last, in September, was their ingress. Yet Wilson, the great ornithologist of America, argues, not without some heat, yet with considerable force, that such a belief is erroneous. Erroneous, certainly, the supposition that the whole body of the Chimney-swifts so hybernate; but whether a few do or do not, his arguments do not quite conclude.

The rustic quatrain, quoted in the outset of this disquisition, mentions the Corncrake, as associated with the Swallow in this winter-sleep,—"in the hollow." It is curious that two modern instances are on record of hybernating Corncrakes, though this is certainly as migratory a species with us as the HirundinidÆ. A farmer at Aikerness in Orkney, about midwinter, in demolishing a mud-wall, found a Corncrake in the midst of it. It was apparently lifeless; but being fresh to the feel and smell, it was placed in the warmth. In a short time it began to move, and in a few hours was able to walk about, and lived for two days in the kitchen; when refusing all food, or rather, none that suited it being then obtainable, it died.[117]

"The second case occurred at Monaghan, in Ireland, where a gentleman, having directed his labourers, in winter, to remove a large heap of manure, that had remained undisturbed for a great length of time, perceived a hole, which was supposed to have been made by rats; it penetrated to a great depth, but at its termination, instead of rats, three Corncrakes were discovered, as if placed there with the greatest care, not a feather being out of its place, and apparently lifeless. The birds on examination were, however, considered to be in a torpid state, and were placed near a fire in a warm room. In the course of a short time a tremulous motion was observed in one of their legs, and soon after a similar motion was noticed in the legs and wings of the whole, which at length extended itself to their whole bodies, and finally the birds were enabled to run and fly about the room."[118]

Daines Barrington, the correspondent of Gilbert White and of Pennant, was a firm believer in the winter sleep of Swallows with us. He mentions, on the authority of Lord Belhaven, that numbers of Swallows had been found in old dry walls and in sandhills near his lordship's seat in East-Lothian; not once only, but from year to year, and that when they were exposed to the warmth, they revived. He says, however, he cannot determine the particular species.[119]

The same naturalist mentions many other instances in which they have been reported to be found, but he cannot give his personal voucher for the truth of the statements.

"As first in a decayed hollow tree, that was cut down near Dolgelly, in Merionethshire; secondly, in a cliff near Whitby, in Yorkshire, where, in digging out a fox, whole bushels of Swallows were found in a torpid condition; thirdly, the Rev. Mr Conway, of Lychton, Flintshire, a few years ago, between All Saints' and Christmas, on looking down an old lead mine in that county, observed numbers of Swallows clinging to the timbers of the shaft, seemingly asleep, and on flinging some gravel on them they just moved, but never attempted to fly or to change their place."[120]

In some communications to the Zoologist for 1845, by the late Mr F. Holme, of Oxford, I find the following statement:—"On the hybernation of this species (the House-swallow) I was told many years since, by old Wall, then keeper of the Kildare Street Museum, in Dublin, ... that after a heavy snow, in the winter of 1825-26, on going into the mansarde to see whether the snow had melted through, he found four Chimney-swallows perched close together on a cross-beam, with their heads under their wings; but on approaching his hand to them they flew off, and escaped into the open air."[121]

Again, Mr J. B. Ellman of Battel, says, "There is a farmer named Waters, residing at Catsfield, (adjoining parish,) who informs me he has frequently (some years ago) dug Swallows out of banks in winter, while widening the ditches in the brooks," &c.[122]

It is unfortunate that most of these and similar discoveries were "some years ago;" and that, instead of increasing in frequency with the increase of scientific research and communication, they strangely become more rare. The same remark applies to the following statement: it is minute enough, and circumstantially precise; but, unfortunately, it was "fifteen years ago." The communicator is Edward Brown Fitton, Hastings, under date September 8, 1849:—

"A labourer named William Joyce, who is now employed in excavating part of the East Hill for the foundation of a house, told me yesterday, that, in the month of December, about fifteen years ago, while he was working for Mr William Ranger, who had the contract for cutting away the 'White Rock,' which used to stand between this place and St Leonard's, the men found an immense quantity of Swallows in a cleft of the rock. The birds were clinging together in large 'clots,' and appeared to be dead, but were not frozen together, the weather being rather warm for the season, nor were they at all putrid or decayed. The men carried out at least three railway-barrows full of birds, which were buried with the mould and rubbish from the cliff as it was wheeled away. Some people from the town carried away a few of the birds to 'make experiments with,' but Joyce never heard any more of them. He mentioned the names of four persons now in Hastings, who were then his fellow-labourers, and says, that forty or fifty of Mr Ranger's men were on the spot when the birds were found, and can confirm what he says, both as to the finding and the very great quantity of the birds. There are many crevices in the seaward surface of the cliffs about here, which apparently penetrate the cliff for several yards. The birds were found about ten feet from the surface of the rock facing the sea, and not very high up."[123]

There is yet another class of facts to be adduced, which has an important bearing on the subject. At first sight, these facts appear less conclusive than the asserted discoveries of the birds, because less direct; but I am inclined to attach more value to them, because they are attested by so many and so unexceptionable witnesses. I mean the sight of Swallows at large in these islands during the winter months. Let us see some examples.

White of Selborne records several cases: thus, in 1773, twenty or thirty House-martins were playing in the air all day on the 3d of November,[124] after having disappeared from the 22d of October. In 1772, he saw three House-swallows gliding by on the sea-shore at Newhaven, on the 4th of November.[125] On another occasion, (the year not being recorded,) he saw, on a sunny morning, a House-martin flying, at Oxford, on the 20th of November.[126] On the 26th of November 1768, one of his neighbours saw a Martin hawking briskly after flies.[127] And a very respectable gentleman assured him that on a remarkably hot day, either in the last week in December or the first week in January, he espied three or four Swallows in the moulding of a window of Merton College, Oxford.[128]

Colonel Montagu remarks that "there are a variety of instances of the Swallow and Martin having been seen flying in the months of November and December, roused probably from a state of torpidity by an unusual warmth of the air;"[129] and Captain H. W. Hadfield, commenting on this, affirms that he has "more than once had ocular proof of their presence during the winter months."[130] Yarrell gives examples of the late appearance of the Swift. One was seen by Mr Blackwall on the 20th of October 1815; a second in Perthshire on the 8th of November 1834; and a third in Devonshire, by the Rev. Mr Cornish, on the 27th November 1835.[131] In considering these cases, it is needful to bear in mind that the Swift migrates from this country annually from the 1st to the 15th of August.

Mr C. R. Bree mentions the following case, which I record, not because it was particularly late, but because the state of the season, and some other circumstances which he remarks on are interesting:—"On the 25th of October 1848, some workmen being engaged on the roof of my house, I was surprised by the appearance of three Swallows flying about the men. I had not seen one since the beginning of the month. By the side of the edge of the gable-end of the house the plaster was broken away, forming a hole, which led under the roof. While watching the birds, which came occasionally quite close to my face, I saw first one, then another, alight upon the ledge of the gable-end, near the hole. Now, I thought, I am to settle the question of hybernation: but I was disappointed. Though I watched them for several hours—though I sent the workmen to another part of the house, yet, although they frequently settled about the hole, they never entered it. They were evidently young birds, and had been disturbed. One of them rested upon the chimney, and appeared weak and dull. I lost sight of them during the day; but the following morning, the weather being warm, I saw several flying about high up in the air. There is some mystery about these things. Why have these late appearances been more remarked this year than other years? How did the birds obtain food during the three weeks of bitter cold weather when they were not seen in October?"[132]

On the 10th of December 1843, a specimen of the Swallow, an adult bird, not a young of the season, (an important circumstance,) in full plumage and good condition, was shot at Goole, in the West Riding, and was sent to Mr R. J. Bell, of Derby, a good ornithologist,[133] who records the fact. In 1852, that excellent naturalist, Mr Hewitson, of Oatlands, saw two Chimney-swallows at Eshar on the 18th of November, and on the 21st had four martins about his house.[134] In 1855, Mr E. Vernon Harcourt reports the occurrence of several Martins skimming about at Uckfield on the 23d of November; and on the 6th of December several Chimney-swallows about the house at Hastings.[135] In the same season flocks of Martins were hawking vigorously, in the vicinity of Penzance, to the 28th of November, as witnessed by Mr E. H. Rodd.[136] Captain Hadfield again, writing in 1856, gives extracts from his journals, whereby he records having seen Swallows and Martins as late as November 3, 1841, December 2, 1842, November 13, 1852, November 22, 1853, November (about the middle) 1854, and November 24 (Swallows) and December 2 (Martins) 1855. Of the last-mentioned occurrence he gives the following interesting note:—"Dec. 2, 4 P.M. Observed eight Martins flying round the garden, and occasionally alighting on the perpendicular face of the wall of a house near my garden gate, to which they would cling for a few seconds, and then, dropping off, whirl round, returning to the same spot, seemingly quite unconscious of my presence and that of several others: they seemed bent on effecting an entrance under the eaves of the house, by a small opening they had discovered near a water-pipe that had been carried through the wall: they were, I believe, all young birds of the season, as they appeared small, their tails being also shorter than in the adults; they were weak on the wing, but that may have arisen from their being benumbed by the cold, the thermometer standing at 44° only at the above hour. There had been a bright sun during the greater part of the day, but I had observed a white frost in the morning. I conclude that these late birds were merely seeking a roosting-place for the night, and not a place of concealment for the winter, although I might have been excused, according to Cuvier, White, &c., had I thought they were taking up their winter quarters; but I have not sufficient faith in the theory to induce me to unslate a part of the roof to seek for them, which might be done, however, at a trifling cost, provided permission were obtained."[137]

It is rather a pity that the observer had not confidence enough to induce him to make the investigation which he suggests.

Mr William Bree mentions as many as fifteen or twenty Martins and Swallows sporting in the air near Temple Balsall on the 18th November 1846, adding that he has frequently seen individuals much later, but never recollects to have seen so great a number together at that late period. And, finally, Mr J. Johnston, jun., reports that he saw, in the afternoon of 18th January 1837, three Swallows dipping and hawking as in summer, near Wakefield.[138]

There is less evidence of the appearance of these birds before the ordinary time of arrival of the migrants. But White, when a boy, observed a Swallow for a whole day together on a sunny warm Shrove Tuesday, which day could not fall out later than the middle of March, and often happened early in February.[139] And Mr Samuel Gurney, jun., together with several other persons, saw either a Martin or Swallow, on the 27th of March 1844.[140]

If this last occurrence had stood alone, it would have been of slight importance; for Yarrell mentions a single Swallow as having been seen by a fisherman near the Eddystone as early as the 4th of April; and Sand-martins, even as far north as Carlisle, before the end of March. It is just possible that these may have been stragglers of the great army of migrants, arriving some ten or fifteen days before their time; but considering the whole great array of evidence, I rather believe that these too were hybernants, who had been prematurely awakened from torpidity by unusually warm days.

The accounts of Hirundines having been found in a somnolent state in winter may or may not be true; though the great number of such statements in various and distant countries makes the indiscriminate rejection of them even more difficult than the acceptance. But still there remains the undeniable fact that it is quite an ordinary thing for birds of this family, including all our four common species, to be seen with us through November and December, and occasionally in January;—that is, for two or three months after the great body of migrants have left the country. No one, I suppose, pretends that migration of Swallows takes place in December or January; therefore it is manifest that a certain number—more or fewer—remain. What becomes of them? We certainly see them only occasionally: where are they on the days on which they do not appear,—days extending to several consecutive weeks? If they had not been torpid during those weeks, if the more active functions of life had not been suspended, would they not certainly have been starved? But the specimen shot on the 10th December, and examined by Mr Bell, was in good condition, which is consistent with but one alternative; either it had been well fed throughout the preceding six weeks, or it had been hybernating. But the former supposition implies that it had been habitually on the wing during that period, as Swallows feed only on the wing; which could not have been the case without its being noticed and recorded.

It is common to say that these occasional winter Swallows are the later broods of young, which, being too infantile to migrate, are compelled to linger in the country of their nativity, and becoming lethargic from the advancing cold, at length die before the spring. But when this hypothesis is looked at, it seems hardly tenable. In many of the instances recorded, the specimens seen even late into the winter, are represented as gaily and vigorously hawking for flies, or sweeping over the water as in summer. This does not look like poor deserted orphans starved with the cold, retiring to die; but birds in health, temporarily awakened from normal slumber by an unusual temperature, and instantly ready for a full use of their faculties. However, to settle the point by fact, Mr Bell distinctly states that his specimen of December 10th was "an adult bird, not a young bird of the season."

If it should be asked why they do not appear in January or February, as well as November and December, the answer is obvious. The winter's lethargy of hybernating warm-blooded vertebrates is much more readily interrupted in the earlier part of the season than in the middle and latter part. And this is natural; for the more intense cold of January benumbs and suspends the vital functions far more completely, and the coma so superinduced is sufficiently deep to resist the counteracting influence of a few warm days, even though the temperature should be as high as on those earlier days that awakened them, or even higher.

The aggregate evidence, then, seems to leave no room for reasonable doubt, that a certain number of our HirundinidÆ,—few, indeed, as compared with the vast migrant population, but still considerable, looked at per se,—for some reason or other, evade the task of a southward flight, and remain, becoming torpid, occasionally betrayed into a temporary activity, and resuming their active life, about the same time, or occasionally a little before the time, of the arrival of their congeners from abroad. It is, however, desirable for the absolute settlement of the question, that specimens, actually discovered in a lethargic condition, should come under the observation of competent scientific naturalists, open to conviction, who would leave them in situ, keeping an eye on them from time to time till the return of warm weather in spring. It is not enough to take them into a warm room, and to shew that they revive in such circumstances: we want to know positively whether they will be resuscitated normally and naturally by the vernal warmth, and come forth spontaneously to sport, and wheel, and skim, and soar, and stoop, and hawk, and twitter,—among their travelled fellows. Who will undertake to decide the point in this manner? He will have achieved a name in science.