LENGTH OF COURTSHIP. 399 



CHAPTER XIV. 



BIRDS— Continued. 



Choice exerted by the female— Length of courtship— Unpaired birds- 

 Mental qualities and taste for the beautiful — Preference or antip- 

 athy shown by the female for particular males— Variability of birds 

 — Variations sometimes abrupt — Laws of variation— Formation of 

 ocelli — Gradations of character— Case of peacock, Argus pheasant, 

 and Urosticte. 



When the sexes differ in heauty, or in the power of singing, or 

 in producing what I have called instrumental! music, it is almost 

 invariably the male who surpasses the female. These qualities, 

 as we have just seen, are evidently of high importance to the 

 male. When they are gained for only a part of the year it is 

 always before the breeding season. It is the male alone who 

 elaborately displays his varied attractions, and often performs 

 strange antics on the ground or in the air, in the presence of the 

 female. Each male drives away, or if he can, kills his rivals. 

 Hence we may conclude, that it is the object of the male to induce 

 the female to pair with him, and for this purpose he tries to ex- 

 cite or charm her in various ways; and this is the opinion of all 

 those who have carefully studied the habits of living birds. But 

 there remains a question which has an all-important bearing on 

 sexual selection, namely, does every male of the same species 

 excite and attract the female equally? Or does she exert a choice, 

 and prefer certain males? This latter question can be answered 

 in the affirmative by much direct and indirect evidence. It is far 

 more difficult to decide what qualities determine the choice of the 

 females; but here again we have some direct and indirect evi- 

 dence that it is to a large extent the external attractions of the 

 male; though no doubt his vigor, courage, and other mental 

 qualities come into play. We will begin with the indirect evi- 

 dence. 



Length of Courtship. — The lengthened period during which 

 both sexes of certain birds meet day after day at an appointed 

 place probably depends partly on the courtship being a prolonged 

 affair, and partly on reiteration in the act of pairing. Thus in 



