Habits and Instincts of the Pairing Season. 221 



With one of the vultures {Gatliartes aura) of the United 

 States, parties of eight, ten, or more males and females 

 assemble on fallen logs, ' exhibiting the strongest desire to 

 please mutually,' and, after many caresses, each male 

 leads off his partner on the wing." These cases appear 

 to have been carefully observed. Still, there is unquestion- 

 ably need of more direct evidence. 



Mr. William Brewster, of Cambridge, Massachusetts, 

 has communicated, and kindly allows me to quote, the 

 following observations, which bear upon the point we 

 are considering : — 



"The case of apparent sexual selection which I men- 

 tioned to you the other 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 

 {Piranga 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 either four or five males— I cannot now 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 coloration. I was con- 

 fident 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 immediate locaHty, and that on the 

 different occasions she looked and acted like the same 



bird." 



" I have written," adds Mr. Brewster, " to Mr. Maynard, 

 inquiring about a similar experience which I think he 

 once had with some red-winged blackbirds." 



