OF NATURAL HISTORY. 481 



and dilappearance of the fwallow-trlbe have given rife to dif- 

 ferent theories and opinions, we fhall briefly relate thofo 

 opinions, and conclude with fome remarks on migration in 

 general. 



Herodotus and Profper Alpinus mention one fpecies of 

 fwallow which refides in Egypt during the whole year* ; 

 and Mr. Loten, late governour of Ceylon, afTured Mr. Pen- 

 nant, that thofe of Java never remove. If thefe be excepted, 

 all the other known kinds retreat or migrate periodically. 

 Swallows migrate from almoft every climate. They remove 

 from Norway f , from North America :}:, from Kamtfchatka§, 

 from the temperate parts of Europe, from Aleppo ||, and 

 from Jamaica 5[. 



Concerning the periodical appearance and difappearance 

 of fwallows, there are three opinions adopted by different 

 natural ifts. The firft and mofl probable, is, that they re- 

 move from climate to climate at thofe particular feafons 

 when winged infecls, their natural food, fails in one country 

 or diftrlcl: and abounds in another, where they likewife find 

 a temperature of air better fuited to their conftitutions. In 

 fupport of this opinion, we have the teftimony, as formerly 

 mentioned, of Sir Charles Wager, of M. Adanfbn, and of 

 many navigators. It is equally true, however, that fome 

 fpecies of fwallows have been occaiionally found in a torpid 

 ftate during winter. Mr. Collinfon gives the evidence of 

 three gentlemen who were eye-witneffes to a number of 

 fand-martins being drawn out of a cliff on the Rhine in the 

 Month of Marcli 1762**. The Hon. Dalnes Barrington, in 

 the year 1768, communicated to Mr. Pennant, on the au- 

 thority of the late Lord Belhaven, the following fadt : * That 



* Profp. Alp, torn. i. page 193, 

 f Pontopp. Hift. Norw. ii. 98. ^ Catelby's Carol, v i. page 51. App. 8. 

 ^ Hid. Kamtrdiatba, page 1 6a. H RufTcl's Alep. page 70. f Phil. Tranf. No. 36. 

 ♦* Philofoph. Trarifadi. vol. S3, P^S^ i°^- ^^^' ^4- 



