402 



HYBERNATION. 



Animals the case, how is reviviscencc produced in the spring ? 

 become *' cannot k e ow ' n g to an y change of temperature, 



Torpid. 



Torpidity 

 of birds. 



for their situation prevents them from experiencing 

 such vicissitudes. Is it not owing to a change which 

 takes place in their constitution ? and, is not awa- 

 kening from torpidity, similar to awakening from sleep ? 

 A similar remark may be made with regard to bats 

 in their winter quarters. The caves to which they re- 

 sort, approach at all times the mean annual temperature. 

 A few individuals, not sufficiently cautious in choosing 

 proper retreats, are sometimes prematurely called into 

 action, at a season when there is no food, so that they 

 fall a prey to owls, and the cold of the evening. But 

 what indications of returning spring have those who 

 are attached to the roofs of the deeper caves ? Surely 

 no increase of temperature ? Perhaps an internal 

 change is the cause which again excites to action. 



There is another very curious circumstance attending 

 the reviviscence of quadrupeds from their torpid state, 

 which deserves to be mentioned. As soon as they have 

 recovered from their slumbers, they prepare for the 

 great business of propagation. This is a proof, that 

 torpidity, instead of exhausting the energies of nature, 

 increases their vigour. It also indicates a peculiarity of 

 constitution, to the preservation and health of which, a 

 brumal lethargy is indispensibly requisite. 



It appears to be the general practice of modern natu- 

 ralists, to treat with ridicule those accounts which have 

 been left us of BIRDS having been found in a torpid 

 state during winter. These accounts, it is true, have 

 in many instances been accompanied with the most ab- 

 surd stories, and have compelled us to pity the credu- 

 lity of our ancestors, and withhold our assent to the 

 truth of many of their statements. But are there no 

 authenticated instances of torpidity among birds ? 



In treating of the torpidity of quadrupeds, we were 

 unable to detect the cause of torpidity, as existing in any 

 circumstances connected with structure or with circula- 

 tion, respiration, oranimal temperature; nor in the places 

 which they frequent, nor the food by which they are sup- 

 ported. Hence we cannot expectmuchhelpfromaknow- 

 ledge of the anatomy, physiology, or even habits of 

 birds, in the resolution of the present question. It has 

 indeed been said, that as birds can readily transport 

 themselves from one country to another, and in this 

 manner shun the extremes of temperature, and reach a 

 supply of food, the power of becoming torpid would be 

 useless if bestowed on them, although highly beneficial 

 to quadrupeds, that are impatient of cold, and cannot 

 migrate to places where there is a supply of food. This 

 mode of reasoning, however, is faulty, since we employ 

 our pretended knowledge of final causes, to ascertain 

 the limits of the operations of nature, and cannot be to- 

 lerated in a science depending entirely on fact and ob- 

 servations. Besides, there are many animals, as we 

 have seen in the class Mammalia, which become torpid, 

 and a similar state obtains among the reptiles. As birds, 

 in the scale of being, hold a middle rank between these 

 two classes, being superior to the reptiles, and inferior 

 to the mammalia, we have some reason to expect in- 

 stances of torpidity to occur among the feathered tribes. 

 These remarks have for their object, to prepare the 

 mind for discussing the merits of the question, by the 

 removal of presumptions and prejudices, as we fear pre- 

 conceived opinions have already exercised too much in- 

 fluence. 



In treating of the migrations of the swallow, we en- 

 deavoured to point out their winter residence, and even 

 traced them into Africa. We are not however prepared 

 to assert, that in every season all these birds leave this 



country. If they remain, in what eondition are they Animait 

 found ? which 



Many naturalists, such as Klein, Linnaeus, and others, ,H ecorn . e 

 have believed in the submersion of swallows during _ 0rr "^ 

 winter in lakes and rivers. They have supposed, that Submersion 

 they descend to the bottom, and continue there until of Swa!- 

 the following spring. Many of the proofs produced in lows- 

 support of this opinion may be found by consulting the 

 article BIRDS, vol. iii. p. 51 1. On this subject we wil- 

 lingly quote the judicious note in the introduction to 

 Bewick's Land Birds. " There are various instances 

 on record, which bear the strongest marks of veracity, 

 of swallows having been taken out of water, and of 

 their having been so far recovered by warmth as to ex- 

 hibit evident signs of life, so as even to fly about for a 

 short space of time. But, whilst we admit the fact, we 

 are not inclined to allow the conclusion generally drawn 

 from it, viz. that swallows, at the time of their disappear. 

 ance, frequently immerse themselves in seas, lakes, and 

 rivers, and, at the proper season, emerge and reassume 

 the ordinary functions of life and animation ; for it 

 should be observed, that in those instances which have 

 been the best authenticated, it appears, that the swal- 

 lows so taken up were generally found entangled 

 amongst reeds and rushes, by the sides, or in the shal- 

 lowest parts of the lakes or rivers where they happened 

 to be discovered, and that having been brought to life so 

 far as to fly about, they all of them died in a few hours 

 after. From the facts thus stated we would infer, that 

 at the time of the disappearance of swallows, the reedy 

 grounds by the sides of rivers and standing waters are 

 generally dry, and that these birds, especially the later 

 hatchings, which frequent such places for the sake of 

 food, retire to them at the proper season, and lodge 

 themselves among the roots, or in the thickest parts of 

 the rank grass which grows there ; that during their 

 state of torpidity they are liable to be covered with wa- 

 ter from the rains which follow, and are sometimes 

 washed into the deeper parts of the lake or river, where 

 they have accidentally been taken up ; and that proba- 

 bly the transient signs of life which they have discover- 

 ed on such occasions, have given rise to a variety of 

 vague and improbable accounts' of their immersion." 

 We may add, that whoever denies that swallows have 

 been found in such situations, let-his reasonings be what 

 they may, tramples under his feet the laws of evidence, 

 and cherishes a scepticism as unphilosophical as the 

 most unthinking credulity. 



But, independent of these instances of submersion, as 

 it is termed, which we regard as purely accidental, 

 there have been many instances of actual torpidity ob- 

 served. Swallows, if we may credit the testimony of 

 many who have been eye-witnesses of the fact, are of- 

 ten found during the winter season in a torpid state in 

 their old nests, and in the crevices of old buildings. 

 The belief of this kind of torpidity is very common in 

 many parts of Scotland, and can scarcely be supposed 

 to have originated from any other cause than the oc- 

 currence of the fact. 



But besides the occurrence of the torpidity of the 

 swallow, Bewick relates an instance of the same condi- 

 tion being observed in the cuckoo. " A few years ago 

 a young cuckoo was found in the thickest part of a 

 close whin-bush. When taken up, it presently disco- 

 vered signs of life, but was quite destitute of feathers. 

 Being kept warm, and carefully fed, it grew and reco- 

 vered its coat of feathers. In the spring following it 

 made its escape, and in flying across the river Tyne it 

 gave its usual call." Brit. Birds, 1. Introd. xvii. 

 There is a still more decided example of torpidity in 



