THEORIES OF MIGRATION 17 



receive them. The author concludes with the sage 

 remark that "if the Moon will not be allowed, some 

 other place must be found out for them" — a state- 

 ment that we may accept, and that we may hope to 

 confirm in the course of the pages to follow. 



In early times, disappearance of certain birds was 

 attributed to hibernation, in which they passed into 

 a torpid state and remained thus through the season 

 of cold, hidden in caves or hollow trees, or embedded 

 in the mud at the bottom of streams, ponds, or 

 marshes. The theory of hibernation seems to find 

 its first expression more than three hundred years 

 before Christ, in the writings of Aristotle, where it is 

 stated that some or all individuals of the swallow, 

 kite, stork, ouzel, turtle-dove, lark, and a number 

 of other species become torpid during winter. Al- 

 though in early times related of many species, this 

 bizarre custom was attributed later mainly to swal- 

 lows, swifts, and, in the United States, to the sora 

 rail; and prolonged and learned were the discussions 

 setting forth the merits of both sides of the case; so 

 that Coues in 1878 cited more than 175 titles dealing 

 directly with hibernation in swallows alone. One 

 early writer published several treatises on the sub- 

 ject, under the pseudonym of "Philochelidon^" 



The sora rail frequented marshes in abundance 

 until between suns it suddenly disappeared. This 



^ Thomas Foster, an author who wrote on othersubjects than birds. 



