82 THE MIGRATION OF BIRDS 



find a chain of islands which would help them, and 

 render the last flight to Japan no longer than the 

 one they had been accustomed to. Having once 

 reached the Midway Islands the shortening of the 

 route would be carried on again by lengthening 

 the oversea journey northwards until the Aleutian 

 Islands were discovered (No. 4). The present 

 route, now followed in spring and autumn (No. 5), 

 would be the natural climax of this long evolution. 

 The two golden plovers, sub-specifically distinct, 

 nest little more than a hundred miles apart ; their 

 migrations and winter homes are as different as 

 they could be in any two widely divergent species. 

 It is one of the most striking of the ascertained facts 

 in the distribution and habits of birds. 



