Chap. VIII. SEXUAL SELECTION. 269 



and with the bullfinch which is said to pair for life. So 

 it is, as I am informed by Mr. Wallace, with the Chat- 

 terers or Cotingidoe of South America, and numerous 

 other birds. In several groups I have not been able to 

 discover whether the species are polygamous or mono- 

 gamous. Lesson says that birds of paradise, so re- 

 markable for their sexual differences, are polygamous, 

 but Mr. Wallace doubts whether he had sufficient evi- 

 dence. Mr. Salvin informs me that he has been led 

 to believe that humming-birds are polygamous. The 

 male widow-bird, remarkable for his caudal plumes, 

 certainly seems to be a polygamist. 8 I have been 

 assured by Mr. Jenner Weir and by others, that three 

 starlings not rarely frequent the same nest ; but whether 

 this is a case of polygamy or polyandry has not been 

 ascertained. 



The Gallinaceae present almost as strongly marked 

 sexual differences as birds of paradise or humming- 

 birds, and many of the species are, as is well known, 

 polygamous ; others being strictly monogamous. W T hat 

 a contrast is presented between the sexes of the poly- 

 gamous peacock or pheasant, and the monogamous 

 guinea-fowl or partridge ! Many similar cases could 

 be given, as in the grouse tribe, in which the males 

 of the polygamous capercailzie and black-cock differ 

 greatly from the females ; whilst the sexes of the mono- 

 gamous red grouse and ptarmigan differ very little. 

 Amongst the Cursores, no great number of species 

 offer strongly - marked sexual differences, except the 

 bustards, and the great bustard (Otis tarda), is said to 



8 ' The Ibis,' vol. iii. 1861, p. 133, on the Progne Widow-bird. Sot- 

 also on the Vidua axillaris, ibid. vol. ii. 1860, p. 211. On the poly- 

 gamy of the Capercailzie and Great Bustard, see L. Lloyd, ' Game Birds 

 of Sweden,' 1867, p. 19, and 182. Montagu and Selby speak of the 

 Black Grouse as polygamous and of the Bed Grouse as monogamous. 



