and
partly, I suppose, because the competition thus created would be a means
of maintaining efficiency, the females, by common consent, are supposed
to supply the condition under which the pugnacious nature of the male is
rendered susceptible to appropriate stimulation. And so long as the
evidence seemed to show that battles were confined to the male sex, so
long were there grounds for hoping that their origin might be traced to
such competition. But female fights with female, pair with pair, and,
which is still more remarkable, a pair will attack a single male or a
single female; moreover, males that reach their destination in advance
of their prospective mates engage in serious warfare. How then is it
possible to look upon the individuals of one sex as directly
responsible for the strife amongst those of the other, or how can the
female supply the necessary condition? As long as an attempt is made to
explain it in terms of the female, the fighting will appear to be of a
confused order; regard it, however, as part of a larger process which
demands, amongst other essential conditions of the breeding situation,
the occupation of a definite territory, and order will reign in place of
confusion.

But even supposing that the male inherits a disposition to acquire a
suitable area, even supposing that it inherits a disposition which
results indirectly in the defence of that area, how does it obtain a
mate? If the female behaved in a like manner, if she, too, were to
isolate herself and remain in one place definitely, that would only add
to the difficulties of mutual discovery. We find, however, in the
migrants, that the males are earlier than the females in reaching the
breeding grounds, and, in resident species, that they desert the females
and retire alone to their prospective territories, so that there is a
difference in the behaviour of the sexes at the very commencement of the
sexual process. What is the immediate consequence? Since the male
isolates itself, it follows, if the union of the sexes is to be
effected, that the discovery of a mate must rest largely with the
female. This of course reverses the accepted course of procedure. But
after all, what reason is there to suppose that, the male seeks the
female, or that a mutual search takes place; what reason to think that
this part of the process is subject to no control except such as may be
supplied by the laws of chance?

Now, clearly, much will depend upon the r