BIRDS— YOUNG LIKE ADULT FEMALBS. 467 



those possessed by the Eared and Cheer pheasants, would not have 

 been dangerous, and if they appeared during early youth, wouid 

 generally have been transmitted to both sexes. 



In addition to the effects of the partial transference of characters 

 from the males to the females, some of the differences between the 

 females of closely allied species may be attributed to the direct or 

 definite action of the conditions of life." With the males, any 

 such action would generally have been masked by the brilliant 

 colors gained through sexual selection; hut not so with the fe- 

 males. Each of the endless diversities in plumage, which we see 

 in our domesticated birds is, of course, the result of some definite 

 cause; and under natural and more uniform conditions, some one 

 tint, assuming that it was in no way injurious, would almost cer- 

 tainly sooner or later prevail. The free intercrossing of the many 

 individuals belonging to the same species would ultimately tend 

 to make any change of color, thus induced, uniform in character. 



No one doubts that both sexes of many birds have had their 

 colors adapted for the sake of protection; and it Is possible that 

 the females alone of some species may have been modified for this 

 end. Although it would be a difficult, perhaps an impossible proc- 

 ess, as shown in the last chapter, to convert one form of trans- 

 mission into another through selection, there would not be the 

 least difficulty in adapting the colors of the female, independenti 

 of those of the male, to surrounding objects, through the accumu- 

 lation of variations which were from the first limited in their 

 transmission to the female sex. If the variations were not thus 

 limited, the bright tints of the male would be deteriorated or de- 

 stroyed. Whether the females alone of many species have been 

 thus specially modified, is at present very doubtful. I wish I could 

 follow Mr. Wallace to the full extent; for the admission would re- 

 move some difficulties. Any variations which were of no service 

 to the female as a protection would be at once obliterated, instead 

 of being lost simply by not being selected, or from free Intercross- 

 ing, or from being eliminated when transferred to the male and 

 in any way injurious to him. Thus the plumage of the female 

 would be kept constant in character. It would also be a relief if 

 we could admit that the obscure tints of both sexes of many birds 

 had been acquired and preserved for the sake of protection, — for 

 example, of the hedge-warbler or kitty-wren (Accentor modularis 

 and Troglodytes vulgaris), with respect to which we have no suf- 

 ficient evidence of the action of sexual selection. We ought, how- 

 ever, to be cautious in concluding that colors which appear to ua 

 dull, are not attractive to the females of certain species; we should 

 bear in mind such cases as that of the common house-spar- 



" See, on this subject, chap, xxiii. in the 'Variation of Animals and 

 Plants under Domestication.' 



