BRITISH WARBLERS
species, such as the Rook (Corvus frugilegus): these all bear witness to the excitement under which the bird labours. It seems, therefore, that Nature does exercise an effective control over the passions of both sexes of many species in this way, i.e., by the necessary condition of the female only arising at certain definite times, and in her case this control is by some means direct, depending upon internal processes, but in the case of the male indirect, though none the less adequate.
The life of the male from the time that the female commences to lay is a most methodical one; this seems to be the rule of the whole species, and I can nowhere find any deviation from it. He adheres with wonderful precision to the boundaries of his territory, where he can be seen morning after morning in the same tree, pouring out his monotonous song, through May, June, and the greater part of July, even after the young have left their nest and disappeared—some, perhaps, to their winter homes. Not, indeed, till the latter part of that month is there any perceptible change, the first intimation of which—the approach of the moult—is a gradual deterioration of the song. He still, however, keeps to his territory until the end of July, when, warned perhaps by the inevitable change that is taking place in him, he begins to move away and wander into hitherto unexplored land.
During the whole of this period referred to he lives exclusively in his territory, and is most jealous of the intrusion of any other male, fighting him vigorously, the female even joining in the pursuit. As the weeks pass by these combats become so frequent, occurring again and again during the same morning, that I am inclined to think they are prompted largely by a love of play. If this is the case, and they are games only, then they are indeed exceptionally vigorous ones, differing only in their duration from the fights which take place earlier in the season over the possession of the breeding territory. There is no doubt about the genuineness of his excitement, for on the approach of the other male he jerks
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