vi On the Songs of Birds 135 



notes which birds use to communicate with each 

 other. The difficult question whether the true songs 

 have or have not been developed out of these minor 

 utterances I must leave for the present untouched. 



Since the appearance of Darwin's Origin of Species 

 there has been considerable discussion about the 

 origin and meaning of song. In his great work, 

 while developing his theory of sexual selection, the 

 famous naturalist threw out a hint that the vocal 

 powers of male birds might be explained on this 

 hypothesis; and in his Descent of Man he worked 

 out the idea more fully, and supported it by a con- 

 siderable number of facts supplied him by books and 

 correspondents. 1 The theory is, in brief, that the 

 song of the male was developed as a charm to the 

 female in the time of courtship; that the females 

 usually select the best singers among their suitors to 

 be their mates ; and that thus, in the course of ages, 

 the vocal powers have been steadily increased by the 

 process of selection. The most highly-gifted birds 

 are chosen as progenitors, and transmit their powers 

 to their young; while the inferior performers are 

 more likely to remain bachelors, exercising no in- 

 fluence upon the race. 



The evidence which Darwin brought together in 

 support of this view was by no means very strong. 



1 Origin of Species, ed. 1888, vol. i. p. 70 ; Descent of Man, 

 ed. 1, vol. ii. p. 51 foil. 



