THE SINGING BIRDS AND THEIR SONGS. 115 



have probably increased in the same ratio, with the 

 progress of agriculture and the settlement of the 

 coruntry. 



The song of birds is undoubtedly innate ; or rather, 

 birds of the same species have, by their organization, a 

 predisposition to utter certain sounds, when under the 

 influence of certain emotions. Besides their native 

 notes, they will learn those of other birds, when con- 

 fined with them, which they sometimes blend with their 

 native strains. The bobolink, when caged, readily learns 

 the song of the canary, and surpasses the original ; but 

 in his wild state he never deviates from his own pecu- 

 liar medley. There is reason to believe that nature has 

 provided each species of bird with notes, unlike those 

 of other species, as a means by which individuals 

 should be enabled to identify their own kindred. When 

 confined in a cage all birds may become imitative, and 

 in a measure forgetful of their original strains'. 



The song of the bird seems to be the means used by 

 the male, not only to woo the female, but to call her to 

 himself when absent. Before he has chosen his mate, 

 he sings more loudly than at any subsequent period. 

 The different males of the same species seem, at that 

 time, to be vying with one another ; and probably the 

 one that has the loudest and most varied song is most 

 likely to be soon attended by a mate. While the two 

 birds are employed in building their nest, the male con- 

 stantly attends his partner from place to place, and 

 sings less loudly and less frequently than before. This 

 comparative silence continues until the female begins 

 to sit on her eggs. While she is sitting, the male again 

 sings more loudly and incessantly, perched upon some 

 neighboring bough, as if to apprise her of his presence, 

 or perhaps with some incli-nation to entice her away 



