SEXUAL SELECTION 163 



very telling evidence that brilliancy of plumage has a great deal 

 to do with the question of mating : 



" The case of apparent sexual selection which I mentioned to 

 you this evening came to my notice in the spring of 1877, when 

 I was collecting birds at St Mary's, Georgia. Finding a pair of 

 summer tanagers (Pyranga rubra) in an isolated grove of pines, I 

 shot the male. Visiting the place a day or two afterwards, I 

 found that the female had another mate, which I also killed. 

 This was repeated, until, in about a week, I had secured in all 

 four or five males I cannot remember which. These males 

 when arranged in the order in which they had been killed formed 

 a graded series, of which the first was an unusually richly 

 coloured bird, the last an exceptionally dull one, the others 

 representing various intermediate shades or stages of colora- 

 tion. I was confident then and I fully believe now that 

 all these males were successively mated to one and the same 

 female : but my only evidence of this was that I never saw more 

 than one female in this locality, and that on the different occasions 

 she looked and acted like the same bird." J The second case bears 

 out this view: " About the date you say (e.g. 1868 or 1869) I 

 shot three male redwings in one meadow (at Newtonville, Mass.), 

 all over one nest. The first was in high plumage, the second less 

 so, the third quite young, and I left with the female a young bird of 

 the previous year, judging by the absence of red on the wing." 2 



I don't know how evidence of this kind is to be got over. A 

 few more such cases well established, and the matter would be 

 set at rest. 



There is a difficulty in Darwin's theory of Sexual Selection A difficulty 

 which has never, I believe, been satisfactorily dealt with. The ^ arwin > s 

 plumes of the peacock are so monstrously large that they en- theory 

 danger his life. He can fly well with the wind, and peacock 

 shooting is considered good sport. But short flights seem to be 

 all he is capable of, and in some parts of India the natives take 

 advantage of this. "Peafowl run very fast, but the old cocks, 



1 Quoted by Professor Lloyd Morgan from Mr William Brewster of Cambridge, 

 Massachusetts, in Habit and Instinct, p. 221. 



2 Quoted from Mr Maynard, Habit and Instinct, p. 222. 



