times were decked in the most elegant and novel manner would have
gained an advantage, not in the ordinary struggle for life, but in
rivalry with other males, and would have left a larger number of
offspring to inherit their newly-acquired beauty.
CHAPTER XV.
BIRDS continued.
Discussion as to why the males alone of some species, and both sexes of
others, are brightly coloured On sexually-limited inheritance, as
applied to various structures and to brightly-coloured
plumage Nidification in relation to colour Loss of nuptial plumage
during the winter.
We have in this chapter to consider why the females of many birds have
not acquired the same ornaments as the male; and why, on the other
hand, both sexes of many other birds are equally, or almost equally,
ornamented? In the following chapter we shall consider the few cases in
which the female is more conspicuously coloured than the male.
In my Origin of Species (1. Fourth edition, 1866, p. 241.) I briefly
suggested that the long tail of the peacock would be inconvenient and
the conspicuous black colour of the male capercailzie dangerous, to the
female during the period of incubation: and consequently that the
transmission of these characters from the male to the female offspring
had been checked through natural selection. I still think that this may
have occurred in some few instances: but after mature reflection on all
the facts which I have been able to collect, I am now inclined to
believe that when the sexes differ, the successive variations have
generally been from the first limited in their transmission to the same
sex in which they first arose. Since my remarks appeared, the subject
of sexual coloration has been discussed in some very interesting papers
by Mr. Wallace (2. Westminster Review, July 1867. Journal of
Travel, vol. i. 1868, p. 73.), who believes that in almost all cases
the successive variations tended at first to be transmitted equally to
both sexes; but that the female was saved, through natural selection,
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