466 THE DESCENT OP MAN. 



in his more strongly-pronounced red and brown tints," we may 

 conclude that his plumage has been influenced by sexual selection, 

 at least to a certain extent. If so, we may further infer that the 

 nearly similar plumage of the female black-grouse was similarly 

 produced at some former period. But since this period the male 

 black-grouse has acquired his fine black plumage, with his forked 

 and outwardly-curled tail-feathers; but of these characters there 

 has hardly been any transference to the female excepting that she 

 shows in her tail a trace of the curved fork. 



We may therefore conclude that the females of distinct though 

 allied species have often had their plumage rendered more or less 

 different by the transference in various degrees, of characters, ac- 

 quired by the males through sexual selection, both during former 

 and recent times. But it deserves especial attention that brilliant 

 colors have been transferred much more rarely than other tints. 

 For instance, the male of the red-throated blue-breast (Cyanecula 

 suecica) has a rich blue breast, including a sub-triangular red 

 mark; now marks of nearly the same shape have been transferred 

 to the female, but the central space is fulvous instead of red, and 

 is surrounded by mottled instead of blue feathers. The Gal- 

 linace» offer many analogous cases; for none of the species, 

 such as partridges, quails, guinea-fowls, &c., in which the colors 

 of the plumage have been largely transferred from the male to the 

 female, are brilliantly colored. This is well exemplified with the 

 pheasants, in which the male is generally so much more brilliant 

 than the female; but with the Eared and Cheer pheasants (Cros- 

 soptilon auritum and Phasianus wallichii) the sexes closely re- 

 semble each other and their colors are dull. We may go so far as 

 to believe that if any part of the plumage in the males of these 

 two pheasants had been brilliantly colored, it would not have been 

 transferred to the females. These facts strongly support Mr. Wal- 

 lace's views that with birds which are exposed to much danger 

 during incubation, the transference of bright colors from the male 

 to the female has been checked through natural selection. We 

 must not, however, forget that another explanation, before given, 

 is possible; namely, that the males which varied and became 

 bright, whilst they were young and inexperienced, would have 

 been exposed to much danger, and would generally have been de- 

 stroyed; the older and more cautious males, on the other hand, 

 if they varied in a like manner, would not only have been able to 

 survive, but would have been favored in their rivalry with other 

 males. Now variations occurring late in life tend to be trans- 

 mitted exclusively to the same sex, so that in this case extremely 

 bright tints would not have been transmitted to the females. On 

 the other hand, ornaments of a less conspicuous kind, such as 



1" Macgilllvray, 'Hist. British Birds,' vol. i. pp. 172-174. 



