166 THE STORY OF THE BIRDS 



the first to go, then late broods may delay others. 

 So far as I have been able to ascertain, the 

 general Order of migration is as follows. The 

 first individuals of a species to migrate are birds 

 that have lost their eggs or young, or from 

 some cause have been prevented from breed- 

 ing during the previous season. Following 

 these are many young birds and their parents, 

 the males in many species preponderating ; 

 then comes a rush of migrants, in which females 

 may be the most abundant ; whilst the rear is 

 brought up by laggards kept behind from a 

 variety of causes, such as damaged wings. The 

 normal course of autumn migration, then, is for 

 young birds to predominate in the earlier stages 

 of the movement, adult birds towards the close. 

 In spring this order is to some extent reversed. 

 Then the adult males generally take absolute 

 precedence, the old females travel next ; the 

 young of the previous season, the more or less 

 immature individuals follow (in some cases 

 these latter apparently spending the summer 

 south of the breeding area), whilst, last of all, 

 come the weakly and crippled. 



The question now may naturally arise : How 

 do birds find their way on migration across so 

 many miles of land and sea ?. Here the greatest 



