226 
sexual selection: birds. 
PakI 
It 
mented with bright tints. It would appear that fenW 0 
birds, as a general rule, have selected their mat® 
either for their sweet voices or gay colours, but n ° 
for both charms combined. Some species which a 1 ® 
manifestly coloured for the sake of protection, 
as the jack-snipe, woodcock, and night-jar, are ^' e ', 
wise marked and shaded, according to our stand® 1 
of taste, with extreme elegance. In such cases " e 
may conclude that both natural and sexual select 0 ® 
have acted conjointly for protection and ornam eIlt ' 
Whether any bird exists which does not possess 
special attraction, by which to charm the opposite & 
may be doubted. When both sexes are so obscur 
coloured, that it would be rash to assume the a g eJlC ' 
•ely 
of sexual selection, and when no direct evidence 
c®® 
be advanced shewing that such colours serve as a F r ° 
tection, it is best to own complete ignorance of tl10 
cause, or, which comes to nearly the same thing; ^ 
attribute the result to the direct action of the c0l) 
ditions of life. 
cOF 
There are many birds both sexes of which are 
spicuously, though not brilliantly coloured, such 
the numerous black, white, or piebald species ; 
these colours, are probably the result of sexual 
ieF 
bl® 0 * 
tion. With the common blackbird, capercailzie, - p 
cock, black Scoter-duck (Oidemia), and even with of 
of the Birds of Paradise ( Lophorina atra), the >° a ^ 
alone are black, whilst the females are brown or )|l0 _ f 
tied; and there can hardly be a doubt that black 11 ® ^ 
in these cases has been a sexually selected char® 0 e 
co# 
rck 
bh' 
Therefore it is in some degree probable that the 
plete or partial blackness of both sexes in such ^ 
as crows, certain cockatoos, storks, and swans, and 111 
marine birds, is likewise the result of sexual se g , 
tion, accompanied by equal transmission to both sc^ 
