124 THE BIRD WATCHER 
thing, though here—ag@l this is significant—the differ- 
ence, as well as the actual colour, is less striking. 
These varying degrees of brilliancy of colouring in 
this particular region, as between the mature and im- 
mature form, must surely have some meaning, and as 
it goes hand-in-hand with a similar, if not, as I believe, 
an identical difference in the hue of the naked facial 
integument, as well as with the pattern and shade of 
the plumage, I feel persuaded that all three are governed 
by the same general law. 
As explained by Darwin—and nothing better, that 
I can see, than opposition has ever been opposed to 
his views—the beauty of certain birds has been ac- 
quired through the principle of sexual selection, and 
the lesser degree of it, which we notice in the young, 
represents the earlier and less-finished beauty of the 
adult in times gone by. Of all the elements which go 
to make up the beauty thus acquired, colour, on the 
whole, plays the most conspicuous part, and nothing 
can be more brilliant and striking than some of the 
colours that I am here speaking of. The only reason, 
therefore, why, in their use, and the laws that have 
governed their acquirement, they should be thought 
to differ from the hues and tintings of the plumage, or 
of the naked outer skin—the cere or the labial region 
—would be their habitual, necessary concealment. If, 
then, it can be shown that, far from their being 
always concealed, they are prominently displayed 
during the breeding season by certain birds which 
possess them in a marked degree, then, as far as 
