BRITISH WARBLERS
advantage. We should then have to regard them solely as practice for the more serious side of life. But none of these possibilities are fulfilled; the conflicts are not of the type that would justify our relegating them to the category of "play" in Professor Groos's sense of the word; they are no less intense, though admittedly less frequent in occurrence, than those which occur after the arrival of a female; they bear the impress of earnestness, and, if I interpret them aright, are directly related to invasion of territory and thus become one stage in a series of events, which follow one another in orderly sequence and make towards the goal of reproduction. In considering the determining influence of territory as opposed to that of the female, can we attach any significance to a contest between two females described in the life of the Whitethroat? Certainly not, if it were simply an accidental departure from the normal routine of female activity. But further observations show that it was no mere isolated incident, though the evidence is scarcely sufficient to admit of such behaviour being spoken of as a general accompaniment of the sexual life of birds. So long as the evidence seemed to show that a direct appeal to strength was the special prerogative of maleness, so long were we justified in regarding the possession of a female as a possible incentive; we now know however that male will fight with male, female with female, pair with pair, and that even male and female will combine to attack a single male or a single female. Here then we have a complexity of strife which is very difficult to explain if it be attributed primarily to an impulse in the male to acquire a female; and if it does not spring from the securing and defence of a territory, I know not in what direction to seek the real factor.
The working of the whole theory of breeding territory is explained in some detail in the earlier part of the life of the Reed Warbler. I have there made some attempt to show how by its assistance we can interpret, on the one hand, the singular desertion of the females by the males in the race to the breeding grounds, the equally singular banishment of
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