BRITISH WAEBLERS 



same territory. This may have been the cause of a struggle 

 I once witnessed, towards the end of May, between two 

 Lesser Spotted Woodpeckers (Dendrocopus minor) and one 

 Great Spotted Woodpecker (Dendrocopus major) ; the latter 

 bird defending a decayed tree, in which possibly its nest 

 was situated, against the onslaughts of the former birds. 

 I have recently gained some further evidence upon this 

 point, for I had an opportunity of watching a conflict between 

 a Great Spotted Woodpecker and a pair of Green Woodpeckers 

 for the possession of a hole in an oak tree. The struggle 

 was carried on intermittently for some days, and as far as 

 actual strength was concerned the Great Spotted Woodpecker 

 was no match for its rivals, but remarkably persistent, and 

 although pecked mercilessly whenever, in the absence of the 

 Green Woodpeckers, it took possession of the hole, yet it 

 refused to leave the locality. Struggles between closely allied 

 species may in reality be of more common occurrence, and may 

 exercise a greater influence, than is generally supposed ; 

 amongst the Warblers at least there is no doubt that such 

 is the case, for Willow Warblers and Chiff-chaffs on the one 

 hand, and Blackcaps and Garden Warblers on the other, are 

 constant rivals. 



The limits of a territory must be influenced by the 

 conditions of existence of the species. Swamps overgrown 

 with the common reed (Arundo phrag 'mites) not being found 

 everywhere, the territory of the Eeed Warbler is consequently 

 small, and has, no doubt, been reduced gradually to the 

 minimum size necessary for the welfare of the species. If the 

 dimensions had been similar to those of the territory of the 

 Chiff-chaff, the species would have rapidly disappeared. 

 Hence there is a point beyond which a species in any one 

 particular district cannot increase, no matter how favourable 

 the conditions of existence may otherwise be. Nevertheless 

 it is probable that this point will seldom be reached, for I can 

 well imagine that the very fact of territory being of such 

 importance as to necessitate one male fighting with another 



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