Page:The British Warblers A History with Problems of Their Lives - 8 of 9.djvu/30

 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 territories, 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 interpretations fail, however, to carry conviction when the attempt is made to explain the presence of vocal extravagances, excessive 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