Habits and Instincts of the Pairing Season. 2 1 5 



sometimes at prepared places. But ornaments of many- 

 kinds, the most brilliant tints, combs and wattles, 

 beautiful plumes, elongated feathers, top-knots, and so 

 forth, are by far the commonest means. In some 

 cases mere novelty appears to have acted as a charm. 

 The ornaments of the males must be . highly important 

 to them, for they have been acquired in not a few 

 cases at the cost of increased danger from enemies, 

 and even at some loss of power in fighting with their 

 rivals. The males of very many species do not assume 

 their ornamental dress until they arrive at maturity, 

 or they assume it only during the breeding season, or 

 the tints then become more vivid. Certain ornamental 

 appendages become enlarged, turgid, and brightly coloured 

 during the act of courtship. The males display their 

 charms with elaborate care, and to the best effect ; and 

 this is done in the presence of the females. The court- 

 ship is sometimes a prolonged affair, and many males 

 and females congregate at an appointed place. To 

 suppose that the females do not appreciate the beauty 

 of the males, is to admit that their splendid decorations, 

 all their pomp and display, are useless ; and this is 

 incredible. . . . 



" If it be admitted that the females prefer, or are 

 unconsciously excited by, the more beautiful males, then 

 the males would slowly but surely be rendered more and 

 more attractive through sexual selection." 



Such are the essential features of the theory of sexual 

 selection. Like the theory of natural selection, with 

 which it has obvious points of relation, but, as we shall 

 see, important points of difference, it attempts to account 

 for the selection of given variations in colour, plumage, 

 and vocal or other activity, and does not profess to give 

 any account of the mode of origin of these variations. It 



