1 82 DOMESTICATED ANIMALS 



found in the crows and their kindred, a group of extremely 

 sociable creatures, which are endlessly engaged in chattering 

 communications with each other. All these forms are highly 

 domesticable, and if for any reason they had proved perma- 

 nently attractive to men they would doubtless have been 

 brought into the state of willing captives. 



Although some of the free-flying or tree birds have been 

 kept for their beauty alone, the greater part of them have 

 commended themselves to man because of their voices. It 

 is hardly necessary to tell the reader that the birds, of all 

 animals, are most provided with means of expression through 

 the voice. There is hardly a species which has not a greater 

 range of notes or calls than the most vocal of our wild mam- 

 mals, and many varieties are impelled to tuneful expression in 

 a measure which no other creature, not even man, exhibits. 

 In most cases these utterances are pleasing to the human ear, 

 for they have the quality which we term musical. There- 

 fore it is not surprising that the most of our captive birds 

 have been chosen for their song. 



It seems clear that the song of birds, like their calls the 

 two shade indefinitely into each other expresses a sympa- 

 thetic emotional consciousness of the actions going on about 

 them, particularly of the life of their kind. In general these 

 utterances are directed toward their kindred of their own 

 species. In many cases, however, as among the imitative 

 birds, the sounds which they utter indicate a curiously keen 

 interest in the actions of their masters or other human affairs. 

 The mocking-birds and some other species will, with great 

 assiduity, endeavor to copy any sound which they happen 

 to hear. I well remember watching a mocking-bird which was 

 listening with rapt attention to the noise produced by a man 



