268 THE BIRD WATCHER 
—a double process ofggexual selection seems the only 
available explanation. Only when the female is plain 
and unadorned, and the male gaudy, does it seem 
prima facie evident that the latter, alone, has been 
selected for his beauty. But it is just this last class of 
cases that has attracted the largest amount of notice, 
for, as might have been expected, it is precisely here 
that we find the males—often the most ornate of birds 
—indulging in the most extraordinary antics, which, 
of course, arrest attention. In observing these birds, 
however, the sexes are at once, and without difficulty, 
distinguished, and as the females do not share in such 
antics, we assume, when we see similar ones on the 
part of birds, the sexes of which are indistinguishable, 
that here, also, the same law holds good, though there 
is by no means the same presumption that this should 
be the case. Confronted with a certain effect, which 
implies a corresponding causal process, in one case, we 
assume this same process in another, though we can- 
not there see the effect. We see, for instance, one 
stock-dove manifestly court another, and at once 
assume that the courting bird is the male. The 
courtship, as is often the case, ends in a pretty severe 
battle, where blows with the wing are given and 
received on either side. We may be surprised to see 
the female so belligerent, but we do not yet doubt the 
fact of her being the female. The courting bird is, at 
last, repelled, and a fight of much the same description 
takes place between him and another stock-dove. This 
one might just as well be a female as the first, but in 
