leave this ground, as presently they will, and return to their territories in the surrounding neighbourhood, and that there each one will fight if necessary to preserve its acre from intrusion.
It would seem, then, from this that the fighting must bear some relation to the particular area of ground in which it occurs; and unless it can be shown that there is some other factor in the external environment of the male, that is the direction in which we must look for the condition under which the instinct is rendered susceptible. One's thoughts turn, of course, to the female, but she too passes backwards and forwards between the territories and the neutral ground, and if her presence were really a conditio sine qua non of the strife, one would like to know why, when she leaves those territories and joins the flock and the males do likewise, similar conflicts should not prevail there also.
Other species have their neutral ground, but the environment seldom affords such facilities for observation as does that of the Lapwing. Even though the Moor-Hens, who are so conspicuously intolerant upon the pool, do feed together amicably upon the meadows adjoining; and the Chaffinch that is so pugnacious in the morning, does seek out the flock later in the day; yet their conditions of existence prevent our obtaining a panoramic view of the whole proceeding, and we have to study each scene separately before discovering that the relation-
