BEITISH WARBLERS 



of the secondary sexual characters. If this were really true , 

 the weaker males would thus be eliminated and an appeal 

 to the law of battle unnecessary. Thirdly, that it is almost 

 inconceivable that such terribly severe struggles should have 

 been developed if they were not of some direct benefit to the 

 victorious individuals ; and, lastly, that in the event of such 

 a further selection taking place, cases of males possessing 

 a territory and yet not attaining to reproduction ought, as 

 already pointed out, to be of not uncommon occurrence. And, 

 having regard to the very meagre evidence upon which is 

 founded that part of the sexual selection theory which would 

 refer the victory to those males that were enabled to excite 

 the females in the highest degree, and considering, too, the 

 very strong evidence in favour of the question of reproduction 

 being decided by a law of battle, it is difficult to resist the 

 conclusion that the latter is the means by which the weaker 

 individuals have been debarred from transmitting their defects 

 to the race. 



The fighting of the females, if it can be shown to be charac- 

 teristic of a number of species, will have an important bearing 

 on this whole question. In discussing the theory of sexual 

 selection in the life of the Grasshopper Warbler, I stated as 

 one of my principal objections to that theory that the ultimate 

 production of the most healthy and most beautiful offspring 

 by the selection of certain males is, without a corresponding- 

 selection amongst the females, impossible, and of the existence 

 of such a selection in any form there is no evidence ; and upon 

 this point I see no reason to alter my views. In fact, further 

 consideration seems to me to add to rather than detract from 

 the force of this objection. For it must be borne in mind that 

 what we are in reality aiming at is the maintenance of the 

 strength of the species, and in thus stating my objection I 

 wished to make it clear that in order to attain this end an 

 elimination of the weaker females is as necessary as an 

 elimination of the weaker males. Strength and beauty cannot 

 be separated, and even if it were ultimately proved that there 



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