BRITISH WARBLERS 



the exact position of those males that have, on the average, 

 passed the test of fitness ; without it the males would have 

 no means of proclaiming the fact that they possessed terri- 

 tories, and would be in well-nigh as hopeless a position, so 

 far as reproduction were concerned, as those which lacked the 

 necessary qualifications for securing a territory. It must 

 therefore be regarded as one link in a chain of events, and 

 we must . be careful not to fix our attention on it alone to 

 the exclusion of the remainder with which it seems so clearly 

 to be connected. This seems to me to have been done in 

 certain interpretations, wherein it is made to play a part 

 independently of accompanying behaviour. Such interpreta- 

 tions fail, however, to carry conviction when the attempt is 

 made to explain the presence of vocal extravagances, ex- 

 cessive motor reactions, and the law of battle in one and the 

 same individual. 



Although the nest is usually commenced soon after the 

 arrival of a female in a territory, yet much variation can be 

 observed in this respect in the case of different individual pairs. 

 Thus one female will lay the foundations of her nursery three 

 or four days after she arrives, whereas another will delay for a 

 week or so. The later females seem eager to commence the 

 construction of their nests, the earlier arrivals less anxious to 

 do so. The actual task of building is left in a great measure 

 to the female, and she sometimes shows hesitation at the 

 commencement as to the choice of a suitable position ; a few 

 pieces of decayed vegetation are laid crosswise here, a flimsy 

 foundation is constructed there, and then she transfers her 

 attention to another bush before setting to work in earnest. 

 I cannot recollect finding more than one or two of these 

 initial attempts in the case of the same individual in the 

 same season, but a few pieces of dead herbage loosely crossed 

 might easily escape detection. These unsuccessful attempts 

 at construction are not confined to this one species ; they are 

 a peculiarity of others, and I am aware of no interpretation 

 which adequately explains them. Such flimsy platforms do 



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