Chap. XIV.l SEXUAL SELECTION : BIRDS. 95 



CHAPTER XIV. 



BiEDS — 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 Pheas- 

 ant, and Urosticte. 



Whex the sexes differ in beauty, in the power of singl- 

 ing, or in producing what I have called instii;mental mu- 

 sic, it is almost invariably the male whicli excels the fe- 

 male. These qualities, as we have just seen, are evidently 

 of high importance to the male. Wlien they are gained 

 for only a part of the year, this is always shortly before 

 the breeding-season. It is the male alone who elaborate- 

 ly 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 

 all 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 excite 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 bear- 

 ing on sexual selection, namely. Does every male of the 

 same species equally excite and attract the female? or 

 does she exert a choice, and prefer certain males ? This 

 question can be answered in the affirmative by much di- 



