BRITISH WARBLERS 



the boundary; this proximity gave rise to constant warfare 

 between her mate and the owner of No. 3 territory, so long as 

 she adhered to that situation, and, I believe, explained her 

 desertion and the construction of another home in the centre 

 of the territory. A bird may desert its nest on account of 

 disturbance, but this particular female forsook a position of 

 security for one of great danger. And, as if to leave us proof 

 that the question of safety did not enter into her con- 

 sideration, she constructed a third nest within a few feet 

 of her second, and in as dangerous a position. Is there no 

 significance in her building a second, a third, and a fourth nest 

 in the centre of the territory, and the second female doing- 

 like wise with regard to her one ? Interesting as this desertion 

 of the nest may be, it is not so peculiar as the polygamous 

 habit of the male. Amongst certain birds polygamy is not 

 uncommon, but it is contrary to the general practice of the 

 smaller birds, and this one instance is the only evidence that 

 so far has come under my notice of any tendency in such a 

 direction amongst the Warblers. I cannot, therefore, help 

 thinking that the case is an unusual one. On the appearance 

 of the second female scenes ensued similar to those which 

 occurred upon the arrival of the first ; that is to say, the 

 expression of emotion was identical in both cases. The male 

 again flapped his wings and again pursued and fluttered in 

 the wake of his second mate, and she likewise went through 

 the customary process of wing-flapping. It is noteworthy 

 that the male attacked the second female on her first appear- 

 ance, but ultimately yielded to her persistent intrusion, and 

 also that the first female seemed to object always to her 

 presence. The single malformed egg laid by the first female 

 in the third nest is possibly not without meaning. May it not 

 point to sexual exhaustion on the part of the male, and may it 

 not consequently be indirect evidence that polygamy is not 

 customary on his part ? It must be within the power of most 

 species to rear two broods at least in one season, and thus be 

 able to replace the destruction of the first. Indeed, it is not 



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