Page:The British Warblers A History with Problems of Their Lives - 6 of 9.djvu/34

 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 consideration, 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 likewise 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 appearance, 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