BRITISH WARBLERS
and I regret this, for even a slight acquaintance is sufficient to show that the species stands high in the scale of emotional development.
In England the bird inhabits wide stretches of common land where heather and gorse grow in profusion, the favourite resort of Stonechat and Meadow Pipit. It is the only warbler that stays with us throughout the year, but whether it remains in family parties or in pairs during the winter, or whether it pairs for life, I am unable to say. Towards the end of February they can be seen in couples, male and female together, and their behaviour seems to show that they are then paired. One can observe the different pairs in the same position day after day, and there is little doubt that they own territories after the manner of other species. For the size of the bird the territories are large, some 250 square yards or so in extent, but it is by no means easy to follow the same pair for a long period, since they move rapidly from place to place and diving into the thickest parts of the heather and gorse are soon lost to sight. Where a number of different pairs occupy adjoining territories there is evidence of much emotional reaction on the part of the males, the meaning of which is not easy to determine in the absence of daily records of the whole period of sexual activity, but the question of territory seems to dominate the situation. Each day one witnesses a more or less similar routine. For periods of varying lengths neither song nor call-note can be heard nor manifestation of excitement seen. But suddenly a change comes over the scene, the birds move restlessly about their respective territories, males come into contact with one another, and we then have the conditions which lead up to an emotional situation. I found these emotional scenes of frequent occurrence at the latter end of February and during the first few days of March, and yet the majority of the males affected seemed to be paired. One or two females were sometimes close at hand, but there was often no visible sign of their presence, and I have no reason to believe that the
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