138 RELATION OF SONG TO THE TERRITORY 



which formerly elicited response become relatively 

 neutral. 



Hence the appearance of the female on the 

 scene marks the opening of a new stage in the 

 life-history of the male, and, to judge by the 

 course of events, it would seem as if the song 

 with its network of relationships had now served 

 its main biological purpose. 



And now, what is the purpose, and what the 

 origin, of song ? Is it, as some naturalists have 

 conceived, a means of raising the emotional tone 

 of the female, of creating a more effective pairing 

 situation, and so of removing a barrier to the 

 successful discharge of the sexual function ; or, 

 is the emphasis here too much upon the 

 emotional, too little upon the strictly utilitarian, 

 aspect? All, I think, will agree that it must 

 serve some biological purpose, and the position 

 we have so far reached is that the determining 

 condition of its manifestation is not merely the 

 establishment, but the actual occupation of a 

 territory, and that there are no factors in the 

 external environment which can evoke response 

 in the absence of such condition. This being so, 

 the further questions arise as to whether it 

 contributes towards the attainment of the end 

 for which the whole territorial system has been 

 built up, and what precisely is the way in which 

 it does so. 



Everyone knows that in the spring the 

 shyest of birds no longer practise the art of 

 concealment. The Curlew soars to a great 

 height, and upon outstretched wings hovers in 



