BRITISH WARBLERS 



development during coition. That these different actions of 

 the male as well as the various degrees of activity which he 

 exhibits are similar in origin must, I think, be admitted, 

 whether we consider they have a meaning in relation to some- 

 thing in the external environment of the female or not. They 

 indicate that highly excited condition of the nervous system 

 which is the prelude to the actual discharge of the sexual 

 function, and in the gentle quivering or the rapid fluttering 

 of the wings we are but observing different stages in the 

 sexual process. There is a tendency, generally speaking, for 

 the intensity of the activity feelings to increase gradually until 

 the culmination is reached, the final effort being productive 

 of the most violent motor reactions, and, judging by behaviour, 

 the first appearance of a female does not necessarily evoke the 

 pairing hunger of the male in the highest degree. Some 

 definite stage of development of the ovaries may be necessary 

 before the female can adequately stimulate the sexual response 

 of the male. Of the attitudes assumed by the female at this 

 period there is little to be said, a partial spreading of the 

 wings in sympathy with the excitement of the male being all 

 that I have definitely observed. 



On frequent occasions excitement is shown by the male, 

 when in the presence or proximity of the female, by an 

 excessive use of his vocal powers, and in most instances 

 the cause can be traced to the presence of an intruding 

 male or an individual of another species; yet there are times 

 when he is alone with her and yet warbles excitedly for a few 

 moments in succession, and even picks up and carries decayed 

 vegetation of some description. Concerning the song at this 

 period, the most noticeable feature is its gradual decrease after 

 the appearance of a female. Previous to this the male sings 

 incessantly, usually from some tree or group of trees prominent 

 in his territory; but this phase of his behaviour undergoes 

 a distinct change upon her arrival. Periods of greater or less 

 duration are then passed in complete silence, and it is difficult 

 to resist the conclusion that his comparative silence is in some 



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