IDENTITY OF THE MALE 45 



congenial enough to entice them to disperse. 

 But may they not have been composed of 

 males that had failed to secure territories, or 

 of females that had failed to discover males in 

 possession of territories, or of both ? 



We have seen that, in the case of many 

 species, each male establishes itself in a 

 particular place at the commencement of the 

 breeding season, even though this may mean a 

 partial or perhaps a complete severance from 

 former companions. We must now discuss 

 this fact in greater detail because it is opposed 

 to the views often held regarding the sexual 

 behaviour of birds, and is manifestly of impor- 

 tance when considering the theory of breeding 

 territory. 



First, however, there is a point which 

 requires some explanation. I speak of the same 

 male being in the same place. How can I prove 

 its identity? In the first place it is highly 

 improbable that a bird which roams about 

 within the same small area of ground, makes 

 regular use of a certain tree and a certain 

 branch of that tree, and observes a similar 

 routine day after day, can be other than the 

 same individual. But, apart from this general 

 consideration, are there any means by which 

 individuals of the same species can be identified ? 

 Well, there is variation in the plumage. 

 Supposing we take a dozen cock Chaffinches 

 and examine them carefully, we shall find slight 

 differences in pattern and in colour — more grey 



