OF NATURAL HISTORY. 491 



whole circuit round the Britifli iflands ; for the appearance of the 

 folan geefe is always efteemed by the fifhermen as a certain prefage 

 of the approach of the herrings or pilchards. In quell of food, thefe 

 birds migrate as far fouth as the mouth of the Tagus ; for they are 

 frequently feen off Lifbon during the month of December. 



The crofs-beak, the crofs-bill, and the filk-tail, are likewife enu- 

 merated by Mr White as birds of pafTage. ' But thefe,' fays he, 

 ' are only wanderers that appear occafionally, and are not obfervant 

 * of any regular migration *.' 



The long-legged plover, and fanderllng, vifit us in winter on- 

 ly ; and it is worthy of remark, that every fpecies of the curlews, 

 wood-cocks, fand-pipers, and plovers t> which forfake us in the 

 fpring, retire to Sweden, PoUand, Pruffia, Norway, and Lapland, 

 both to feed and to breed. They return to us as foon as the 

 young are able to fly ; becaufe the frofts, which fet in early in thefe 

 countries, totally deprive them of the means of fubfiftance. For 

 the fame reafon they leave us in fummer, as the drynefs and hard- 

 nefs of the ground prevent them from penetrating the earth with 

 their bills in queft of worms, which conftitute the natural food of 

 thefe birds. 



From the fads which have been enumerated, and from 

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

 land and water kinds, migrate from one climate to another. But, 

 even in the fame climate and country, birds occafionally perform 

 partial migrations. During hard winters, when the furface of the 

 earth is covered with fnow, many birds, as larks, fnipes, &c. retire 



3 Q^a from 



• White's Natural Hiftory of Selborne, pag. 1 18. 



f Linn. Amoen. Acad. torn. 4. pag. 588. Klein de Avium Migrat. pag. 187. 



