and the latter a greater or lesser degree of pleasurable excitement raised by it with a choice in accordance, which is sexual selection. And that the display would come at last to be made intelligently, and with a view to a proposed end—as in the case supposed of the female wild duck (or other bird) diverting attention from its young—I can also understand. In both instances mere nervous movements due to a high state of excitement would have been directed into a certain channel and then perfected by the agency either of natural or sexual selection.
On this view the curiosity (passing insensibly into interest and satisfaction) of the female bird would have been directed, at first, not to the plumage but to the frenzied actions—the antics—of the male, and he, on his part, would have first consciously displayed only these. From this to the more refined appreciation of colours and patterns may have been a very gradual process, but one can understand the one growing out of the other, for waving plumes and fluttering wings would still be action, and action is emphasised by colour.
Where, however, such movements had not been seized upon and controlled by the latter of these two powers—i.e. sexual selection—(and there is no necessity that they should be), we should have antics not in the nature of sexual display properly speaking, but which might yet bear a greater or less resemblance to such. That this is, in fact, the case has been pointed out by the opponents of sexual selection, and often as if it were evidence against it (though no one, unfortunately, can point to men as a ground for disbelief in armies). Mr Hudson, for
