SUMMARY 117 



with such desperation. And surely success will 

 be attained by that pair whose emotional tone 

 stands high and whose impulse to fight is there- 

 fore strong, rather than to the ill-assorted couple. 



The argument, then, is briefly this. In the 

 spring, a marked change takes place in the 

 character of the males of very many species ; 

 instead of being gregarious they either avoid one 

 another and become hostile, or, if their con- 

 ditions of existence require that they shall 

 still live together, they become irritable and 

 pugnacious. This change is made known to us 

 by the battles of varying degrees of severity 

 which are such a feature of bird life in the 

 spring ; and since a female can commonly be 

 observed to accompany the combatants, the 

 possession of a mate appears at first sight to be 

 the proximate end for which the males are 

 contending. But when the circumstances which 

 lead up to the quarrels are investigated closely, 

 the problem becomes more difficult ; for it is 

 not merely a question of males fighting in the 

 presence of a female, as is generally supposed to 

 be the case, but on the contrary there is a com- 

 plexity of strife which is bewildering — males 

 attack females or vice versa: female fiohts 

 with female ; or a pair combine to drive 

 away another pair, or even a solitary individual 

 no matter of which sex. This complexity of 

 strife makes against the view that the possession 

 of a mate is the reason of the fighting. But an 

 even stronger objection is to be found in the fact 



