EEED WARBLER 



hen is more vividly coloured than the male, and it is possibly 

 she who defends the territory, attacks all intruders, and 

 exhibits the pugnacity referred to, although it is difficult to 

 make certain of this, since the difference in colouring and 

 size between the sexes is so slight that at a distance it is 

 not very easy to distinguish them. The question we arc 

 attempting to answer is what is the cause of the battles, and 

 whether an individual of one sex does really struggle for 

 possession of one of the other sex. When the righting is 

 confined to one sex only, we might be justified, providing 

 there were no evidence to the contrary, in assuming that the 

 opposite sex was the immediate cause. But in the case of the 

 Whitethroat we have a species in which the males are more 

 brightly coloured than the females and struggle amongst them- 

 selves, but in which, contrary to expectation, the females also 

 fight with one another. Of what advantage could it be to any 

 species for the males to struggle for the females, and for the 

 females to struggle for the males ? This fact of the females 

 fighting is therefore one of some importance, since it points to 

 the existence of some other factor as the true cause of the 

 battles. Among the large number of individuals that annually 

 migrate together, it must sometimes happen that two females 

 settle in the same occupied territory, and under these circum- 

 stances what could be more natural than that one should 

 attempt to drive the other away ? The ultimate object of 

 such a battle may be said to be the male : this much I con- 

 cede ; but another factor is introduced by the law of territory, 

 with the result that it matters not w r hether the male possesses 

 any special attractiveness, so long as the more important 

 consideration be fulfilled, namely, that he be the owner of a 

 territory. The question, then, which remains to be answered is 

 to what extent a law of battle does exist amongst the females. 

 I mentioned at the time that in no other species had I 

 seen the females fighting, but I have since been lucky 

 enough to see two more instances. Both sexes of the Moor- 

 hen aid in the defence of their territory, as do both sexes of 



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