BRITISH WARBLERS 



hesitation which is assumed to be an essential prelude to con- 

 jugation. Elsewhere I have suggested that such a use of the 

 term is open to criticism. And since it is possible that from 

 the moment a sexually mature female enters the territory of 

 a single male the question of reproduction is decided, pro- 

 viding always that she is not challenged and defeated by a 

 rival of the same sex, I have referred, in the later parts of 

 this work, to the whole of the period commencing with the 

 arrival of the female and ending with the laying of the normal 

 number of eggs as that of sexual activity. During this period 

 the emotional manifestation, which is unequalled at any other 

 period in volume though sometimes not in intensity, may 

 perhaps be said to reach its climax during the actual dis- 

 charge of the sexual function, and the manifold and peculiar 

 antics and attitudes which we witness must be regarded as 

 part of a whole — that is to say, as part of the sexual instinct. 

 The problem, then, which requires a solution is the exact 

 position that these activities occupy in the whole sexual pro- 

 cess ; but so long as we are ignorant of so many simple facts 

 in the lives of so many species, it is scarcely likely that a 

 satisfactory solution will be reached. 



If it were possible to induce one pair of each of our more 

 common species of warblers to rehearse its life-history before 

 an onlooker previously unacquainted with their habits, one 

 feature which would perhaps command a large share of his 

 attention would be the fact that each species has its own 

 degree of response, which is constant even at the different 

 emotional periods. He would notice that this pair was per- 

 sistently sluggish in behaviour, while that pair was scarcely 

 able to restrain its excitement on the slightest provocation. 

 In all likelihood he would thereupon call to mind all he knew 

 of human emotion, and possibly satisfy himself that an analogy 

 was to be found in the behaviour of the different races of man. 

 And so long as the analogy were limited to this particular 

 feature, it would approximate in some measure to the actual 

 facts. We enter in the latter part of April some wood in- 



6 



