170 TERRITORY AND REPRODUCTION 



to glance at the life-histories of divergent forms 

 to see that the territory has been gradually ad- 

 justed to suit their respective needs — limited in 

 size here, expanded there, to meet new conditions 

 as they arose. Now some may think that the 

 theory would be more likely to be true if the 

 territory had but one purpose to fulfil, and 

 that one the same for every species ; and they 

 may see nothing but weakness in the multiplica- 

 tion of ways in which I shall suggest it may 

 be serviceable. But such an objection, if it 

 were raised, would arise from a mistaken con- 

 ception, a conception which, instead of starting 

 with a relationship and working up to the 

 " territory," sees in the " territory " something 

 of the bird's own selection and thence works 

 back to its origin. Holding the view that it 

 is nothing but a term in a complex relationship 

 which has gradually become interwoven in 

 the history of the individual, I see no reason 

 why the fact of its serving a double or a treble 

 purpose should not be a stronger argument 

 for its survival. I now propose to examine 

 the various ways in which the territory may 

 have been of use in furthering the life of the 

 individual, and the circumstances in the inorganic 

 world which have helped to determine its 

 survival. 



The purpose that it serves depends largely 

 upon the conditions in the external environ- 

 ment—the climate, the supply of food, the 

 supply of breeding-stations, and the presence 

 of enemies. Hence its purpose varies with 



