SWALLOWS: THEIR HIBERNATION. 263 



near their place of retreat. On the same day, more than 

 twenty house-martins appeared, which had retired with- 

 out exception on the 7th day of the October previous. 

 He adds that whenever the thermometer is above 50°, 

 the bat flits out during any autumn or winter month. 

 The author concludes that two whole species of swal- 

 lows, or at least a large proportion of them in Great 

 Britain, never leave the island, but remain torpid in some . 

 place of retreat ; for he remarks, " We cannot suppose 

 that, after a month's absence, house-martins can return 

 from Southern regions, to appear for one morning in 

 November ; or that house-swallows should leave the 

 districts of Africa, to enjoy in March the transient 

 summer of a couple of days." 



Daines Barrington testifies that he has in many in- 

 stances known martins to reappear during warm days in 

 different parts of the winter, but he is not sure that he 

 has 'ever seen swallows at such times. He thinks, there- 

 fore, that martins conceal themselves in crevices of rocks, 

 from which on a warm day they can emerge ; but swal- 

 lows, which are buried under water, cannot feel the influ- 

 ence of a short period of warm weather. The treatises 

 on Ornithology written in the northern parts of Europe 

 allude frequently, as if it were an established fact, to the 

 submersion of swallows during the winter. Peter Brown, 

 a Norwegian painter, informed Mr. Barrington that while 

 he was at school near Sheen, he and his comrades con- 

 stantly found swallows in numbers torpid under the ice 

 that covered bays, and that they would revive if placed 

 in a warm room. The author of a paper read before the 

 Academy of Upsal mentions the submersion of swallows 

 as a known fact in that part of the world. Among the 

 superstitions associated with this belief, Pantoffidan re- 

 lates that swallows before they sink under water sing the 

 Swallow Song, as it is called, and which everybody knows. 



