COMPLEXITY oi Tin: IK, HUM, 87 



prevails between neighbouring pairs, and which 

 can be observed in the life of many other 

 species the Chaffinch, Stonechat, Blackbird, 

 I 'artridge, Jay, to mention but a few. 



The conflicts between males that are 

 definitely paired are of such common occurrence 

 that it is scarcely necessary to mention specific 

 instances. But the occasions on which a male 

 attacks either sex of a neighbouring pair indis- 

 criminately, or on which a pair combine to 

 attack a female, are less frequent. 



Now if it be true that males fight for no other 

 purpose than to gain possession of a mate, what 

 meaning are we to attach to the battles between 

 the pairs, or what explanation are we to give 

 of the fact that paired males are so frequently 

 hostile ? Those who hold this view will prob- 

 ably argue thus : " The presence of the female 

 is the condition under which the pugnacious 

 instinct of the male is rendered susceptible 

 to appropriate stimulation, and the stimulus 

 is supplied by a rival male ; we admit that 

 all the fighting which occurs after pairing has 

 taken place has nothing to do strictly speak- 

 ing with gaining a mate, but, inasmuch as the 

 fact of possession is always liable to be challenged 

 and no male can differentiate between a paired 

 and an unpaired intruder we contend that it 

 would add to the security of possession if the 

 pugnacious instinct remained susceptible to 

 stimulation so long as there were any possibility 

 of challenge from an unpaired male ; and we 

 think that the waste of energy involved in 



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