BIRDS. 11 



Migrations Acquired notes. 



main behind, and lie concealed in hiding places 

 until the return of spring and that the cold of 

 winter benumbs and renders them torpid. On 

 the other hand, the actual migration of the swal- 

 low tribe has been demonstrated by a number of 

 well authenticated facts, taken from the observa- 

 tions of navigators, who have been eye-witnesses 

 of their flights, and who inform us that the rig- 

 ging of their ships have often been covered with 

 the weary travellers. These accounts, indeed, 

 so frequently occur in the narratives of voyages, 

 that we cannot doubt of their authenticity, nor 

 of the reality of these migrations. However, 

 after all the enquiries of naturalists into this mys- 

 terious branch of animal economy, the subject 

 remains involved in no small degree of obscurity; 

 and, after all our researches, we cannot deter- 

 mine into what regions of the globe these little 

 animals migrate, 



" Amusive birds, say where your hid retreat, 

 When the frost rages and the tempests beat ; 

 Whence your return, by such nice instinct led, 

 When spring, sweet season ! lifts her bloomy head ? 

 Such baffled searches mock man's prying pride j 

 The God of Nature is your secret guide," 



It appears from observation, founded on nu- 

 merous experiments, that the peculiar notes of 

 the different species of birds, are altogether ac- 

 quired, and are no more innate than language is 

 in man. The attempt of a nestling to sing, may 

 be exactly compared with the imperfect en dea- 

 lt 2 



