MIGRATION. 



ocular demonstration, for many weeks together, both 

 spring and fall ; during which periods, myriads of 

 the swallow kind traverse the Straits from north to 

 south, and from south to north, according to the 

 season. And these vast migrations consist not only 

 of hirundines, but of bee-birds, hoopoes, oro pen- 

 dolos, or golden thrushes, &c. &c. and also of many 

 of our soft-billed summer birds of passage ; and 

 moreover, of birds which never leave us, such as 

 all the various sorts of hawks and kites. Old Belon, 

 two hundred years ago, gives a curious account of the 

 incredible armies of hawks and kites which he saw 

 in the spring time traversing the Thracian Bospho- 

 rus, from Asia to Europe. Besides the above men- 

 tioned, he remarks that the procession is swelled by 

 whole troops of eagles and vultures. 



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 ; but then I can- 

 not help wondering 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 migrations, by reason of vast oceans, 

 cross winds, &c. ; because, if we reflect, a bird may 

 travel from England to the Equator without launch- 

 ing 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 



