The Descent of Man

ous animals, than a smaller open nest. Nor
must we forget that with many birds which
build open nests, the male sits on the eggs and
aids the female in feeding the young: this is the
case, for instance, with Pyranga aestiva (11.
Audubon, 'Ornithological Biography,' vol. i. p.
233.), one of the most splendid birds in the United
States, the male being vermilion, and the
female light brownish-green. Now if brilliant
colours had been extremely dangerous to birds
whilst sitting on their open nests, the males in
these cases would have suffered greatly. It
might, however, be of such paramount importance
to the male to be brilliantly coloured, in
order to beat his rivals, that this may have more
than compensated some additional danger.
Mr. Wallace admits that with the King-crows
(Dicrurus), Orioles, and Pittidae, the females
are conspicuously coloured, yet build open
nests; but he urges that the birds of the first
group are highly pugnacious and could defend