136 MIGRATION. 



Now, it is no wonder that birds residing in Africa should 

 retreat before the sun as it advances, and retire to milder 

 regions, and especially birds of prey, whose blood being 

 heated with hot animal food, are more impatient of a sultry 

 climate ; bnt then I cannot help wandering why kites and 

 hawks, and such hardy birds as are known to defy all the 

 severity of England, and even of Sweden and all north 

 Europe, should want to migrate from the south of Europe, 

 and be dissatisfied with the winters of Andalusia. 



It does not appear to me that much stress may be laid on 

 the difficulty and hazard that birds must run in their migra- 

 tions, by reason of vast oceans, cross winds, &c. ; because, if 

 we reflect, a bird may travel from England to the Equator 

 without launching out and exposing itself to boundless seas, 

 and that by crossing the water at Dover, and again at 

 Gibraltar. And I with the more confidence advance this 

 obvious remark, because my brother has always found that 

 some of his birds, and particularly the swallow kind, are 

 very sparing of their pains in crossing the Mediterranean ; 

 for when arrived at Gibraltar, they do not, 



" Ranged in figure, wedge their way 

 and set forth 



Their airy caravan, high over seas 



Flying, and over lands with mutual wing 



Easing their flight ; " MILTON. 



but scout and hurry along in little detached parties of six or 

 seven in a company ; and, sweeping low, just over the sur- 

 face of the land and water, direct their course to the opposite 

 continent at the narrowest passage they can find. They 

 usually slope across the bay to the south-west, and so pass 

 over opposite to Tangier, which, it seems, is the narrowest 

 space. 



In former letters, we have considered, whether it was 

 probable that woodcocks, in moonshiny nights, cross the 

 German Ocean from Scandinavia. As a proof that birds of 

 less speed may pass that sea, considerable as it is, I shall 

 relate the following incident, which, though mentioned to 

 have happened so many years ago, was strictly matter of 

 fact : As some people were shooting in the parish of 



