BRITISH WARBLERS 



able by selection to breed a race of game-cocks which fight to 

 a finish. Conflicts between the male Willow Warblers on 

 different boundaries are of frequent occurrence, and, at the 

 commencement of the season when two appear to lay claim 

 to the same territory, of some duration, the ruffled feathers 

 denoting the severity of the struggle. At such times their 

 flight is rapid. They pursue one another amongst the bushes, 

 or close to the ground, and when they meet there is an audible 

 clicking of bills and the impact is considerable. To some 

 extent they are oblivious of what is taking place around them, 

 and in their intense eagerness I have seen two combatants 

 pass within a few feet of where I was standing. When they 

 settle, after such encounters, they show signs of considerable 

 excitement, jerking their wings, and giving vent to their feel- 

 ings by a single or else by a purring note. In the case of 

 males with adjoining territories, the conflicts are not so pro- 

 longed, and perhaps on the whole not so severe ; they may be 

 better described as incessant quarrels arising from trespass of 

 boundary on the part of' some individual. These contests 

 continue for some weeks, but gradually become less and less 

 frequent. From this description I do not wish it to be sup- 

 posed that a male can never cross its boundary without being 

 attacked, for such is not the case. At the same time I wish 

 it to be clearly understood that, when I speak of a boundary, 

 it is an imaginary one fixed by myself as the result of obser- 

 vation. Nevertheless it is possible to establish with consider- 

 able accuracy the true limits of a territory, though these 

 limits may be intruded upon without a conflict occurring. 



The second cause of disturbance referred to, namely, the 

 antipathy shown by this species to the presence of a Chiff-chaff 

 — possibly a mutual antipathy — is interesting. It results in 

 frequent quarrels and conflicts, for a pair of each species often 

 inhabit the same territory. Sometimes one is the aggressor, 

 sometimes the other ; but the Willow Warbler seems to me to 

 be more often the cause of the strife. The battles resemble 

 those that take place between the males of the same species, 



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