136 RELATION OP SONG TO THE TERRITORY 



founded upon a congenital basis; it is truly 

 instinctive, and as such requires appropriate 

 stimulation ; furthermore the male sings only 

 when in occupation of its territory. Having 

 regard to these two facts we might say that 

 the territory is the stimulus to the song. But 

 this can scarcely be a true interpretation, for 

 inasmuch as the stimulus would be relatively 

 constant, a relatively constant response ought to 

 follow, and even a slight acquaintance with the 

 daily round of behaviour will furnish plenty of 

 evidence to the contrary, seeing that the song, 

 though persistent, is never continuous — in fact 

 there are long periods of silence during the 

 daytime, and only in the morning and the 

 evening does the male become really vociferous. 

 What then is the stimulus ? Through aware- 

 ness of something in the environment the male 

 responds to stimulation, and the only reply we 

 can give is that the headquarters, or a distant 

 song, or the proximity of another male — with 

 all of which, as we have seen, the instinct is 

 definitely related — are the specific factors which 

 normally evoke response — and experience teaches 

 us that the periods of quiescence are just those 

 when life is at its lowest ebb and these stimu- 

 lating factors less in evidence. Bearing this in 

 mind, bearing in mind the fact that when a male 

 joins the flock or crosses the boundary its 

 instinct ceases to respond, bearing in mind, 

 that is to say, that there is evidence of relation- 

 ship between these specific factors and the 

 song only when the territory is actually occu- 



