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]