270 RELATION OF TERRITORY TO MIGRATION 



its individuality, and all its inherited instincts 

 which then come into operation lead to its 

 isolation from the flock. The impulse to seek 

 isolation is dependent upon internal organic 

 conditions which are peculiar to a certain 

 season ; whereas the gregarious impulse depends 

 upon internal organic conditions which inhere 

 at all times, though its functioning is inhibited 

 by the functioning of the former impulse. The 

 evidence which leads to this conclusion is to 

 be found in the fact that a male often deserts 

 its territory temporarily and joins the flock, 

 where it remains at peace with its companions — 

 an aspect of behaviour which we have discussed 

 on various occasions. The former impulse be- 

 comes dominant in the spring owing to its 

 innately superior strength ; the latter becomes 

 dominant in the autumn because the organic 

 condition which determines the functioning of 

 the former then subsides. The impulse to 

 seek the appropriate breeding ground and to 

 dwell there would seem to be the strongest 

 of all the impulses save one — the sexual. 

 When, however, I speak of the sexual, I 

 refer to the actual discharge of the sexual 

 function, which is the consummation of the 

 whole process. But the territory and all that 

 appertains to it is part of that process — the 

 search for the breeding ground, the dwelling 

 there, and the intolei'ance of intrusion are but 

 different stages, each one of which must 

 have an impulse peculiar to it ; and since the 

 completion of the sexual act can only be 



