2 INTRODUCTION 



a simple mental process we conceive of a state 

 in bird life analogous to that which we know 

 to be customary amongst ourselves. Now, 

 although the term "breeding territory," when 

 applied to the sexual life of birds, is not alto- 

 gether a happy one, it is difficult to know 

 how otherwise to give expression to the facts 

 observed. Let it then be clearly understood that 

 the expression " securing a territory " is used to 

 denote a process, or rather part of a process, 

 which, in order to insure success to the indi- 

 vidual in the attainment of reproduction, has 

 been gradually evolved to meet the exigencies 

 of diverse circumstances. Regarded thus, we 

 avoid the risk of conceiving of the act of secur- 

 ing a territory as a detached event in the life of a 

 bird, and avoid, I hope, the risk of a conception 

 based upon the meaning of the word when 

 used to describe human as opposed to animal 

 procedure. 



Success in the attainment of reproduction is 

 rightly considered to be the goal towards which 

 many processes in nature are tending. But 

 what is meant by success ? Is it determined by 

 the actual discharge of the sexual function ? 

 So many and so wonderful are the contrivances 

 which have slowly been evolved to insure this 

 discharge, that it is scarcely surprising to find 

 attention focused upon this one aspect of the 

 problem. Yet a moment's reflection will show 

 that so limited a definition of the term " success " 

 can only be held to apply to certain forms of 

 life ; for where the young have to be cared for, 



