110 DISPOSITION TO DEFEND THE TERRITORY 



The various steps by which the territory is 

 not only established but made secure from 

 invasion, imply an inherited nature nicely 

 balanced in many directions — first of all the male 

 must be so attuned as to be ready to search for 

 a territory at the right moment ; then it must 

 be capable of selecting a suitable environment ; 

 and, having established itself, it must be prepared 

 to defend its area from a rival, and to resist 

 encroachment by its neighbours — and if it failed 

 in any one of these respects, it would run the 

 risk of failure in the attainment of reproduction. 

 Each individual has therefore to pass, so to 

 speak, through a number of sieves — ^the meshes 

 of which are none too wide — before it can have 

 a reasonable prospect of success. This being so, 

 we ask, in the first place, whether the female, 

 too, may not have an eliminating test to pass ; 

 and in "the second place, whether she may not 

 also assist in furthering the biological end of 

 securing the territory. 



Now the answer to the first of these 

 questions will be found to be in the affirmative. 

 Just as, in the securing of a territory, the ultimate 

 appeal is to the physical strength of the male, 

 so, in the course of her search for a mate, the 

 female may be called upon to challenge, or may 

 be challenged by a rival, and the issue is decided 

 by force. My attention was first drawn to this 

 fact by a struggle between two female White- 

 throats, which I have described elsewhere. The 

 scene of its occurrence was the corner of a small 

 osier bed occupied by one male, and the females 



