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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.
