i88 MIGRATION OF THE WILLOW WARBLER 

 that a family of these warblers sets out on a 

 journey from England to Africa. Starting 

 from an inland place they have first to find 

 their way to the coast, where, possibly, they 

 fall in with other migrants bound in a southerly 

 direction ; but being weak fliers they are 

 unable to keep pace, and so are thrown on 

 their own resources, viz., the supposed know- 

 ledge possessed by the parent birds of the 

 route from England to Africa. Once out at 

 sea, landmarks disappear and occasional fogs 

 are encountered, to say nothing of the fact 

 that birds on migration fly mostly at night, 

 resting by day or on reaching land. However, 

 after travelling thus for many days and nights, 

 and covering anything over i,ooo miles, the 

 party duly arrives, and from this one experi- 

 ence the young birds must be prepared, in six 

 months' time, to retrace every mile of the way 

 back, for by that time they will have become 

 separated and lost to one another. (-Most, if 

 not all, male warblers arrive in advance of the 

 females.) 



If this case is insufficient to prove that it is 

 not parental guidance which enables young 

 birds to find their way to far distant climes, we 

 shall turn to a migrant who can learn nothing 

 from its parents: namely, the familiar cuckoo. 



The cuckoo, with its hawk-Uke appearance. 



