Part 19

Richardson's Borderer's Table Book, iii. 92.

Zool., 3266.

Zool., 6941.

Zool., 613.

See page 183, ante.

Zool., 4245.

HYBERNATION OF SWALLOWS.

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--

"The bat, the bee, the butterfly, The cuckoo and the swallow, The corn-crake and the wheat-ear, They all sleep in the hollow."

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

"The corn-crake and the nightingale."

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 Am{oe}nitates 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."

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." 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."

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.

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.

"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."

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.

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.