162 RELATION OF SONG TO THE TERRITORY 



gation, we can infer that if a male had no 

 certain means of advertising its position, the 

 territory would not be brought into useful 

 relation in its life. Have we here sufficient 

 ground on which to construct a theory of 

 origin ; in other words, has the evolution of 

 song been incidental to, and contributory to, 

 the evolution of the territory ? 



We have all along spoken of the song and 

 of the call-notes as if they were manifestations 

 of separate emotional states having their respec- 

 tive and well-defined spheres of usefulness ; 

 and while, speaking generally, this is a true 

 statement of the case, there is much evidence 

 to show that the relationship between them 

 is nevertheless very close. There are, for 

 example, quite a number of cases in which a 

 particular call-note is uttered with unusual 

 energy during sexual emotion, and is attached 

 to the song, of which it may be said to form a 

 part ; but a still closer connection can be traced 

 in many simple melodies which are merely 

 compositions of social and family calls repeated 

 many times in succession, and even in some 

 of the more complex productions there will 

 be found indications of a similar construc- 

 tion. And since this is so, since moreover, 

 in the seasonal vocal development of such a 

 bird as the Yellow Bunting, we can observe 

 the gradual elaboration from simple to com- 

 plex — from the repetition of single notes to 

 phrases and from phrases to the complete 

 melody- — we have every reason to suppose that 



