i6o BIRDS OF THE PLAINS 



from chestnut to white in the third year of his 

 existence. 



Darwin, as I have aheady pointed out, devoted much 

 time and energy in trying to prove that there is in most 

 species competition among males for females, and that 

 these latter are in consequence able to exercise a selec- 

 tion. They choose the most brilliant and beautiful of 

 their numerous suitors. Thus we have what he calls 

 sexual selection, or, as I should prefer to call it, feminine 

 selection. On this theory the poor cock exercises no 

 selection ; any decrepit old hen is good enough for 

 him ! He is all eagerness, while the hen is blase and 

 indifferent. This theory is, I submit, improbable on 

 a priori grounds. It is certainly opposed to human 

 experience, and is, I believe, not borne out by animal 

 behaviour. 



I have paid some attention to the subject lately, and 

 am convinced that in most cases the desire of the hen 

 for the cock is as great as the desire of the latter for the 

 hen. It was only this morning that I watched two hen 

 orioles trying to drive each other away, while the cock 

 was in a tree near by. 



To repeat what I have already said, the hen courts 

 the cock quite as much as he courts her. When a 

 pair of birds mate they are mutually attracted to one 

 another. That there is such a thing as sexual selection 

 I am convinced, but I do not believe that this selection 

 is confined to the hens. The hen selects the best cock 

 she can get to pair with her, while the cock selects the 

 best hen available. 



I speak here of monogamous species ; among poly- 



