492 THE PHILOSOPHY 



from the inland parts of the country to the fea-fhores, where they 

 pick up a fcanty fubfiftance. Others, as the wren, the red-breaft, 

 and many of the fmall birds, or fparrow-kind, refort to gardens, and 

 the habitations of men. Their intention, it is obvious, is to procure 

 food and flielter. 



There are three principal objefts of migration : Food, tempera- 

 ture of air, and convenient fituations for breeding. Such birds as 

 migrate to great diftances are alone denominated birds of p off age. 

 But all birds are, in fome meafure, birds of paflage, though they do 

 not migrate to places fo remote from their former abodes. At par- 

 ticular times of the year, moft birds migrate from one county to 

 another, or from the more inland diftrids toward the Ihores. Thefe 

 partial migrations of fmall birds arc well known to bird-catchers, 

 who' make a liveliehood by enfnaring them into their nets, and fell- 

 ing them. The birds^?)', as the bird-catchers term it, about the end 

 of September, and during the months of Odober and November. 

 There is another, but lefs confiderable, flight in March. Some begin 

 their flight annually about Michaelmas; others, as the wood-larks, 

 fucceed, and continue their flight till the middle of Odtober; but 

 the green-finch does not migrate till the froft obliges it to remove in 

 queft of food and fhelter. Thefe partial migrations, or flittings, are 

 performed from day-break till noon. Another, but fmalier, flight 

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

 times when particular birds migrate from one fituation to another 

 are well known to the bird-catchers, who, by means of call-birds, 

 nets, and other devices, feize great numbers of them, and, after ac- 

 euftoming them for fome time to rcftraint and flavery, fell them, for 

 confiderable prices, to curious men and whimfical women. A dili- 

 gent attention to thefe partial migrations, and their motives, would 

 fooQ unfold the caufes of thofe of a more extenfive kind. 



Migration 



