CHAPTER X 



THE PROCESS OF MIGRATION 



In a former chapter were discussed some aspects of the 

 Causes which impel birds to migrate. In the present, are 

 added certain studies on the Process by which that 

 migration is effected. 



The migration of birds is accepted too generally as 

 an article of faith. Its operation (in certain obvious 

 cases) is so patent, that many are content to accept the 

 whole phenomenon on trust without further ado or the 

 trouble of investigation. But inquiry brings its students 

 face to face with facts and circumstances of such difficulty 

 as to shake to its foundations that earlier easy-going faith. 

 That, it may be said, is inherent to the nature of "faith" ; 

 but, in this case, we have means of probing, deeper than 

 in all, towards the bases in actual facts that underlie the 

 unknown. 



We are apt to measure Nature's methods by the 

 standard she has assigned to ourselves alone. Thereby 

 we may create for ourselves difficulties and "marvels," 

 not to say impossibilities, which, if regarded from some 

 more appropriate standpoint, might prove explicable 

 enough. 



How do birds migrate? That is, by what means 

 can such feeble creatures transfer themselves by millions, 



