98 ODD HOURS WITH NATURE 



it is quite simple, though it has been worked out 

 in rather bewildering detail. In the first place, 

 male birds fight with one another for possession 

 of the plumpest, most vigorous, and best -looking 

 females. The strongest succeed, and, in the case 

 of polygamous birds, get the biggest harem, and, 

 in the case of monogamists, the best mates. In 

 both cases the triumphant warrior gives rise to 

 a large progeny of good stock like himself. The 

 vanquished, on the other hand, has to content 

 himself in the one case with a small harem, and 

 in the other with an old, unattractive hen of 

 diminished fertility, with a result of small and 

 feeble progeny. Thus the race is improved by 

 the increase of the good fighting stock and the 

 reduction of the poor fighting stock. In these 

 cases the cock selects the hen. 



To a much greater extent, however, the theory 

 of sexual selection concerns itself with those cases 

 in which the hen is supposed to select the cock. 

 In a great number of cases, as everybody knows, 

 the males of birds are much more magnificently 

 clothed than their mates. The hen peafowl is 

 quite a plain customer, and the same is true 

 through the whole family of pheasants to which 

 it belongs. As a family, this one includes the 

 most gorgeous birds in the world, but all the 

 finely coloured individuals are males. Why? By 

 the theory the males are finely coloured because 

 the hens, themselves plain, have a most remarkably 

 well-developed taste, and, other things equal, will 

 always prefer to ally themselves with the finest 

 cock bird of their acquaintance. In support of 



