DARTF0RD WARBLER 



stimulus to the emotional manifestation in the male was 

 supplied directly by them. Let us examine these emotional 

 scenes more closely. Sexual no doubt they are in origin, in 

 so far as the sexual instinct is the source of all this behaviour, 

 but the instinct more immediately aroused is clearly that of 

 pugnacity. There is a deal of quarrelling and sometimes 

 much fighting. The males follow one another closely from 

 bush to bush, and meeting upon the top of some holly or fir 

 tree or prominent gorse bush, utter their scolding note, warble, 

 or sing, with their feathers in the meantime tightly com- 

 pressed. And when the scene becomes more animated, both 

 males, at different moments or perhaps together, expand one 

 wing and hold it momentarily fully expanded, or expand both 

 wings alternately with great deliberation. The expansion 

 of one wing can be frequently witnessed and may occur whilst 

 the birds are on the ground hopping round and about one 

 another. At any moment, too, their emotions may increase 

 in intensity until the situation becomes one of active hostility. 

 Thereupon they fly at one another often amongst the thick 

 heather, and one can hear the snapping of bills and observe 

 scenes which are customarily associated with hostility. What 

 relation can these activities bear to the female if the males 

 that take part in them are paired and have each their respec- 

 tive mates ? I have even observed a male desert the company 

 of his female, when another male was close at hand, and 

 become an actor in such a scene, so that we cannot regard 

 the presence of an unpaired male as an essential condition 

 of the situation, if, that is to say, my observations are correct. 

 In the absence of sufficient data, one is forced to bring to bear 

 upon the problem knowledge derived from other species. And 

 knowing the part that the struggle for territory plays in the 

 lives of so many different species, we are justified, I think, in 

 believing that it is responsible for the manifestations which 

 we witness. 



I mentioned the expansion of one wing or the alternate 

 expansion of both wings in the case of the male during periods 



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