The Descent of Man

were not eliminated by natural selection, owing
to the protection which they already enjoyed
from their manner of nidification. According to
this view, their present manner of nesting was
acquired before their present colours. But it
seems to me much more probable that in most
cases, as the females were gradually rendered
more and more brilliant from partaking of the
colours of the male, they were gradually led to
change their instincts (supposing that they originally
built open nests), and to seek protection
by building domed or concealed nests. No one
who studies, for instance, Audubon's account
of the differences in the nests of the same species
in the Northern and Southern United States
(20. See many statements in the 'Ornithological
Biography.' See also some curious observations
on the nests of Italian birds by Eugenio Bettoni,
in the 'Atti della Societa Italiana,' vol. xi. 1869,
p. 487.), will feel any great difficulty in admitting
that birds, either by a change (in the strict
sense of the word) of their habits, or through