182 SEXUAL selection: birds. PartIL 



for some distinct purpose, perhaps for gaining a "warmer 

 winter covering ; and that variations in the plumage 

 occurring during the summer were accumulated through 

 sexual selection, and transmitted to the offspring at the 

 same season of the year. Such variations being inhe- 

 rited either by both sexes or by the males alone, accord- 

 ing to the form of inheritance which prevailed. This 

 appears more probable than that these species in all 

 cases originally tended to retain their ornamental 

 plumage during the winter, but were saved from this 

 through natural selection, owing to the inconvenience 

 or danger thus caused. 



I have endeavoured in this chapter to shew that the 

 arguments are not trustworthy in favour of the view 

 that weapons, bright colours, and various ornaments, 

 are now confined to the males owing to the conversion, 

 by meaDS of natural selection, of a tendency to the equal 

 transmission of characters to both sexes into transmis- 

 sion to the male sex alone. It is also doubtful whether 

 the colours of many female birds are due to the preser- 

 vation, for the sake of protection, of variations which 

 were from the first limited in their transmission to the 

 female sex. But it will be convenient to defer any 

 further discussion on this subject until I treat, in the 

 following chapter, on the differences in plumage between 

 the young and old. 



