(whether we include amongst these the bright colouring of the mouth or not), have been acquired by the female also in the same way—that there has been, in fact, a double process of sexual selection instead of a single one only; that the male, as well as the female, has been capable of exercising choice?
Great stress has been laid upon the eagerness of the male, as contrasted with the coyness of the female, in courtship, throughout nature; but were the latter to possess some eagerness also, her share of it need not be so great as the male's, so that we should not, by supposing her to, be contravening this principle: she might even fly, or seem to fly, from his pursuit. How, then, might her own ardour become valid to the extent of influencing the choice of the cock? As it appears to me, this might be brought about through the jealousy inspired in one hen bird by the sight of attentions paid to another. She, the jealous one, might have behaved coyly had the same, or another, male wooed her, but her feelings become inflamed and her modesty is lost when she sees that which, for all her seeming, she would have wished for herself, bestowed upon another. She interposes, let us say, at first, by attacking the favoured female, but if this one is as strong and as determined as herself, there will be now a series of indecisive combats, of which the cock will be the spectator; and why should not these combats be varied with displays, or something of that nature, on the part of either combatant, with the view of attracting him? If so, the cock who has previously,
