MIGRATION OF ANIMALS. 281 



From the facts which have been enumerated, and from 

 others of a similar nature, it is evident, that many birds, both 

 of the land and water kinds, migrate from one climate to 

 another. But, even in the same climate and country, birds 

 occasionally perform partial migrations. During hard winters, 

 when the surface of the earth is covered with snow, many 

 birds, as larks, snipes, &c., retire from the inland parts of the 

 country to the sea-shores, where they pick up a scanty sub- 

 sistence. Others, as the wren, the redbreast, and many of 

 the srnal birds, or sparrow kind, resort to gardens, and the 

 habitations of men. Their intention, it is obvious, is to pro- 

 cure food and shelter. 



There are three principal objects of migration ; food, tem- 

 perature of air, and convenient situations for breeding. Such 

 birds as migrate to great distances are alone denominated 

 birds of passage. But all birds are, in some measure, birds 

 of passage, though they do not migrate to places so remote 

 from their former abodes. At particular times of the year, 

 most birds migrate from one country to another, or from the 

 more inland districts toward the shores. These partial migra- 

 tions of small birds are well known to bird-catchers, who make 

 a livelihood by ensnaring them into their nets, and selling 

 them. The birds Jly, as the bird-catchers term it, about the 

 end of September, and during the months of October and 

 November. There is another, but less considerable flight, in 

 March. Some begin their flight annually about Michaelmas; 

 others, as the woodlarks, succeed and continue their flight 

 till the middle of October ; but the greenfinch does not mi- 

 grate till the frost obliges it to remove in quest of food and 

 shelter. These partial migrations, or flittings, are performed 

 from daybreak till noon. Another, but smaller flight, com- 

 mences at two o'clock, and continues till night approaches. 

 The times when particular birds migrate from one situation 

 to another are well known to the bird-catchers, who, by means 

 of call-birds, nets, and other devices, seize great numbers of 

 them, and after accustoming them for some time to restraint 

 and slavery, sell them for considerable prices to curious men 

 aud whimsical women. A diligent attention to these partial 

 migrations, and their motives, would soon unfold the causes 

 of those of a more extensive kind. 



' Migrating birds, before they take their departure, in gen- 

 eral collect together in flocks, and many of them are known 

 to perform their migrations in company, and to form large and 

 regularly-arranged flocks on their route. Swallows aro well 

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