Any Scout who has not a tree of his own to hang his box on can probably get leave to put it up, if he asks nicely, in some neighbour's wood or garden, or in a park, and can then visit it from time to time to see how it is getting on.
Most nesting-boxes have their roof, or front, on hinges, or made so that it can slide off; but it does not do to examine the nest when once it is made, or the old birds will desert it.
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BIRD MIGRATION.
The movements of birds as they change their quarters still puzzle the naturalists.
It is marvellous how they seem to like travelling, and no one can understand why they take certain paths through the air when they are doing it.
For instance, the black pool warbler, in America, spends its summer in Alaska, and goes down to South America for the winter. It takes the straightest course it can from Alaska to Brazil, flying over land and sea—and a wide sea, too, is the Gulf of Mexico. But the cliff swallow, which also spends the winter in Brazil and the summer in North Canada, takes quite a different route, and goes an extra 2000 miles in order to avoid going over the sea, and follows the land all round by Panama, Nicaragua, Honduras, Guatemala, Mexico, and so through the United States.
The distances which birds cover when "migrating" are enormous. Some American plovers are known to travel for 8000 miles, one part of the journey being 2500 miles without resting as they pass over the sea.
The arctic tern goes even farther, it nests near the North Pole, and then makes its way down to near the South Pole, a journey of 11,000 miles.
Perhaps you wonder how we know that the birds travel these long distances. Well, a good many naturalists and stalkers catch birds when young or tired and mark them by putting a small ring round their leg with a number on it. Then other naturalists keep a look out in other parts of the world, and when they kill or find a bird with such a number on it they report it.