BRITISH WARBLERS
manner which differed but little from that of a few weeks earlier in the season. I can now amplify this a little. The Garden Warbler is not a particularly demonstrative bird; according to our emotional scale it occupies a position midway between the two extremes, and we have placed it in a class by itself. Two methods of expressing sexual emotion on the part of the male are known to me, the more commonplace of the two being that one in which the wings are partially extended, and this is the attitude that is assumed by the female when her nest is intruded upon, providing that the stimulus is sufficiently strong to produce the necessary response. The Willow Warbler is still less demonstrative, but both sexes assume a peculiar attitude previous to coition, and this attitude is again assumed by the female when excited about her offspring. The Grasshopper Warbler is more demonstrative than either of these two previous species. The male spreads and waves its wings during sexual activity, and a similar waving of the wings sometimes takes place in the case of both sexes when excited about their young. In comparing these two periods we must not lose sight of the fact that during sexual activity the motor reactions reach their greatest intensity in the male; but during incubation, or whilst the young still require the care of their parents, in the female; and as the female during sexual excitation shows traces of those reactions common to the male, so the male when excited about its young may affect attitudes similar to those of the female. That the sexual and parental emotion should reach the highest degree of intensity in the male and female respectively is what we should anticipate since it appears to be the rule throughout a considerable part of animal life. Similarity of the organic symptoms in different emotions is not unknown. Professor Lloyd Morgan refers to it as follows[1]: "It would seem then, if there be any truth in the considerations just hinted at rather than developed, that what is
- ↑ "Habit and Instinct," p. 201.
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