Note 24 — Chapter II

For the illustrations of both kinds of selection I must refer the reader to Mr. Darwin's works. In regard to birds, he makes the sexual selection operate less by the "law of battle" among the males, or by fighting, and more by the attractions of plumage and voice, by which the males carry on their rivalry for the choice of the females in pairing. But he attributes the same effect to the sexual selection in birds as in the other animals, namely, the transmission to offspring, and chiefly to the male offspring, of those peculiarities of structure which have given to the male parent the victory over his competitors.