292 Wild Birds and their Haunts 



has been found that swallows kept under water, with all 

 due precautions, die in a few minutes. 



A no less fanciful, but, as it appears to many, a more 

 defensible opinion, was published in a scarce tract, pur- 

 porting to be written by " A Person of Learning and 

 Piety," who maintained with no little ingenuity that our 

 migratory birds retire to the moon. He thinks that they 

 are about two months in passing thither, and that after 

 they are arrived above the lower regions of the air into the 

 thin aether, they will have no occasion for food, as it will 

 not be so apt to prey upon the spirits as our lower air. 



Even on our earth, he argues, bears will live upon their 

 fat all the winter ; and hence these birds, being very succu- 

 lent and sanguine, may have their provisions laid up in 

 their bodies for the voyage ; or perhaps they are thrown 

 iuto a state of somnolency by the motion arising from the 

 mntual attraction of the earth and moon. 



There is a preponderating list of eminent naturalists 

 who favour the idea that swallows migrate, and the gist of 

 their remarks may be very briefly summed up. Birds 

 certainly leave our country. Without disputing that 

 difference of temperature and nourishment have much to 

 do with it, they are inclined to consider, that habit is 

 quite as much concerned ; according to them the recol- 

 lection of the old ones, that they have made the journey, 

 carrying the young with them, and the ' ' instinct of 

 travel," which, at certain periods, affects them with 

 real nostalgia, must be considered, especially the last 

 as the principal and immediately exciting cause of these 

 migrations. Birds of passage, too, always migrate 

 with a contrary wind, which instead of frustrating, really 

 eases and raises them in their flight. 



The late famous M. Brehm puts it thus : ' ' Every bird 

 has its native country, where it freely reproduces, and 

 remains part of the year, travelling in the remainder. 

 Most birds spend half of the time at their home, and pass 

 the other half in travelling. Some, particularly birds of 

 prey, travel by day ; but by far the greater part go by 

 night ; and some perform their migrations indifferently 

 either by day or night. They seem to pass the whole of 



