The Theory of Sexual Selection. 383 
about the same area as the play-house. The flowers 
are said to be removed when they fade, while fresh 
ones are gathered to supply their places. Thus the 
garden is always kept bright with flowers, as well as 
with the brilliant green of mosses, which are col- 
lected and distributed in patches, resembling tiny 
lawns. 
Now these sundry cases alone seem to prove a high 
degree of the esthetic sense as occurring among 
birds ; for, it is needless to say, none of the facts just 
mentioned can be due to natural selection, seeing that 
they have no reference to utility, or the preservation 
of life. But if an zsthetic scnse occurs in birds, we 
shuld expect, on a fgriori grounds, that it would 
probably be exercised with reference to the personal 
appearance of the sexes. And this expectation is 
fully realized. For it is an observable fact that in 
most species of birds where the males are.remarkable 
for the brilliancy of their plumage, not only is this 
brilliancy most remarkable during the pairing season, 
but at this season also the male birds take elaborate 
pains to display their charms before ‘the. females. 
Then it is that the peacock erects his tail to strut 
round and round the hens, taking care always to 
present to them a front view, where the coloration is 
most gorgeous. And the same is true of all other 
gaily coloured male birds. During the pairing 
season they actively compete with one another in 
exhibiting their attractiveness to the females ; and in 
many cases there are added all sorts of extraordinary 
antics in the way of dancings and crowings. Again, 
in the case of all song-birds, the object of the singing 
is to please the females; and for this purpose the 
