On the Migration of North American Birds. 95 



(Hirundo riparia,) which is a native of both continents, and our chim- 

 ney swallow, ( Cypselus pelasgius, Temm.) have occasionally been 

 found in holes on the banks of rivers, in the hollows of decayed trees, 

 or in the recesses of old buildings, clinging together sometimes in 

 great numbers, nearly in a torpid state. Hence it was asserted that 

 these were their winter retreats and that here they remained in a state 

 of torpidity, from the cold of autumn, to the sunny days of spring. 

 This doctrine has been espoused by a number of intelligent naturalists 

 of Europe from the amiable and observing White of Selborne, even 

 to the great Cuvier, who makes use of the following language. " Some 

 birds retire into remote places, to some desart cave, some savage rock, 

 or ancient fortress." He evidently had no opportunities for a sat- 

 isfactory examination. Dr. Good has also asserted of the chaffinch 

 of Sweden, {Fringilla coelebs,) that many of the males indulge in 

 a profound sleep in Sweden whilst the females migrate to Holland 

 towards the winter and duly return to them in the spring. 



From dissection, (the details of which it is unnecessary to give 

 here) it has been ascertained that from the internal structure of swal- 

 lows, and the same may be said of all birds, it is impossible for them 

 to live beyond a day or two in a torpid state. In this declaration I 

 am supported by the investigations of the celebrated John Hunter. 

 I have seen the American chimney swallow as well as the rail pla- 

 ced under the water to try the experiment whether they could exist in 

 that element, and they have invariably been drowned in a few min- 

 utes and no warmth or even electricity could afterwards revive them. 

 The habits of swallows drinking from brooks and rivers, while they 

 are on the wing and of their picking up flies and insects, whilst skim- 

 ming the surface of the water, has no doubt given rise to the decep- 

 tions in persons, supposing that they had seen them going under the 

 water as a winter retreat. When birds of this species have been 

 found in nearly a dormant state, it was either in the autumn or early 

 in the spring, generally the latter. These are the seasons of their 

 migration. At night they sought those retreats, as usual, to sleep ; 

 here, they were overtaken by a cold change in the atmosphere, and 

 here they would have died in a very short time, if the weather had 

 not become milder. These birds have, 1 apprehend, never been 

 found in this situation in winter. Besides, our senses can satisfy us 

 where the swallows spend their winters. Of the six species of swal- 

 lows that inhabit the United States, all of them but the cliiF swallow 

 which has but recently made its appearance in the country are seen 



