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 Cotingidae 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. What 
a contrast is presented between the sexes by 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. See 
also on the Vidua axillaris, ibid. vol. ii. 1860, p. 211. On the poly- 
gamy of the Capercailzie and Great Bustard, see L. Lloyd, 4 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. 
