THE PROCESS OF MIGRATION 127 



cover the enormous distances appointed them ; and (2), 

 how do any birds, weak or strong, so direct their course 

 as to reach their distant points, year after year, with 

 unerring precision? 



The only truthful answer to both these questions, 

 despite all the attention paid to ornithology for centuries, 

 is simple enough : we do not know. 



I will take the second question first. A presumptive 

 reply, which prima facie seems obvious, is that the 

 knowledge of direction is derived from older birds, which, 

 having performed the journey before, are thus enabled 

 to pilot the young. But any such idea collapses when 

 we find that, as a rule, young and old travel separately ; 

 and that, in most cases, the young birds precede the adults 

 in their first migratory flight. Too impatient to wait till 

 their parents have completed the autumnal moult, these 

 mere fledglings set out alone to traverse an unknown 

 world. Very unfilial, no doubt, appears such conduct ; 

 but that they do so is an easily proved fact, well within 

 our knowledge- — some details thereof are set out else- 

 where in this book. 1 We are therefore left (in our blind- 

 ness) with no other resource than to ascribe this 

 juvenile success in steering to that nebulous definition, 

 "inherited instinct." 



Nor, as suggested, can twentieth-century knowledge 

 furnish any more definite reply to the question first 

 above propounded. That long-winged birds such as 

 cuckoos, swallows and swifts, curlews, sandpipers, and 

 even the crows and thrushes, are capable of sustained 

 flight, we can readily imagine. But how can the punier 



1 The following extract from the Migration Report, 1880, p. 66, seems 

 pertinent: — "As a rule the young of the year migrate some weeks in 

 advance of the old birds. This holds good of all orders and species." 



