MARSH WARBLER 



in the lives of other species. What place are we to assign 

 to song in the sexual process? In the life of the Willow 

 Warbler I suggested that it might be of some use in con- 

 nection with the territory, and the means whereby the females 

 are made aware of the presence of males fit to reproduce. 

 But supposing we say that song has a meaning in relation 

 to something in the sexual environment of the female; 

 supposing, that is to say, that her instinctive sexual response 

 will only follow a certain presentation — a necessary part of 

 which is formed by the song — how shall we explain this 

 marked diminution of the song before coition has taken place, 

 and before therefore the utility we postulate can possibly have 

 come into play? Even the gradual slackening of the song- 

 is, in accordance with this view, not altogether easy to under- 

 stand ; for may it not be argued that a waning sexual instinct 

 would require an even more vigorous presentation to arouse 

 the necessary response, and that as the period of sexual 

 activity progressed so the intensity of the song ought to 

 increase rather than diminish ? And yet the converse may 

 be said to be possible, namely, that a response once aroused 

 would be more readily awakened on subsequent occasions. 



There is a point with regard to the sexual behaviour which 

 deserves mention. I became acquainted with this species 

 in Holland before I had an opportunity of doing so in this 

 country, and I was there impressed with the attitudes the 

 males habitually assumed, with, in fact, the intensity displayed 

 in overt expressional movement. Of these attitudes the most 

 striking was that one in which the wings were rapidly raised 

 above the back and as rapidly closed, and has already been 

 referred to. I therefore expected to find that the attitudes 

 assumed by the males in this country would be similar to 

 those already observed, but this expectation has not altogether 

 been fulfilled. How far failure has been due to insufficient 

 observation is difficult to say, but the way is clearly open to 

 error, since we can never be quite sure that the condi- 

 tions under which we observe different individuals entirely 



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