PURPOSE OF SONG 141 



in finding food, and afford mutual protection by- 

 giving timely warning of the approach of a 

 common enemy, and the gregarious instinct is 

 thus of great advantage to the species ; but no 

 matter how powerful the impulse to flock might 

 be, if there were no adequate means of com- 

 munication, the different units would frequently 

 fail to discover their neighbours. Here the 

 specific cries and calls come into play, enabhng 

 them as they move about in search of food, or 

 change their feeding grounds, or whilst they are 

 on migration, to keep constantly in touch with 

 one another ; and hence one purpose that these 

 call-notes serve is that of recognition. Moreover, 

 they convey their meaning to individuals of other 

 species and are acted upon, and are thus in every 

 sense socially serviceable ; but on the other hand, 

 whilst there is much evidence to show that the 

 song is of great individual value, there is none 

 to show that it is in any like manner of direct 

 advantage to the comnmnity. 



If, then, there is in the call-notes an adequate 

 means of communication and of recognition, why 

 do I suggest that the song has also been evolved 

 primarily for the purpose of recognition ? 



What, first of all, are the conditions in the 

 life behaviour during the season of reproduction 

 that make the intervention of the voice a con- 

 sideration of such importance? The general 

 result of our investigation might be summed up 

 thus : we found that the male inherits a disposi- 

 tion to secure a territory, that at the proper 

 season this disposition comes into functional 



