Page:Howard's 'Territory in Bird Life.' - Witmer Stone - The Auk, 38(2) - P0288-p0290.pdf/2

Vol. XXXVIII 1921 when they are establishing the boundaries of their respective "territories." Later on paired males will fight when one enters the "territory" of the other or one male and female will unite in the defence of their domain against a neighboring pair, or a male will drive out an encroaching female or vice versa. Only this theory of an established "territory" as the primary cause of conflict can, in the author's opinion, explain the complicated nature of the fighting that is to be seen every season and in every community. Furthermore neutral grounds may be recognized, unsuited perhaps for nesting, but rich in food supply, where various males as well as females will resort in perfect harmony, just as in the winter flockings, although the very same individuals will engage in strenuous combat if they encounter one another within the confines of their respective "territories." Within each "territory" there is a favorite perch from which the male sings and which Mr. Howard terms the "headquarters." This is the station which Mr. H. Mousley has so fully described as the "singing tree" in his paper in 'The Auk' for 1919, p.339—to which paper by the way our author makes no reference.

The delimitation of the "territory' is accomplished as a result of habit, in visiting certain particular spots or perches, over and over again, in search of food or for other purposes, and while fairly definite the boundaries are of course not absolute.

The need of a "territory," Mr. Howard thinks, lies in the necessity of the parents' securing sufficient food for their young without going so far from the rest as to deprive them of brooding for too long an interval, and he dwells particularly upon the extreme delicacy of young passerine birds and the need of continual protection from cold by brooding.

In other words each nest is by this plan provided with a sufficient food supply immediately around it, which would not be the case were there a community of nests close together. As birds of other species do nest close by and have "territories" of their own with different boundaries, we must naturally suppose that their food is of a different character. No doubt some of our economic ornithologists could furnish data of the greatest interest in this connection and demonstrate why certain species can live in close proximity without affecting each other's food supply.

There are of course species in which many pairs nest in close association. Many of these, as the Guillemots, Mr. Howard considers, represent cases where the question of securing food is subordinate to the question of securing a station suitable for reproduction. With the Guillemots the nearby ocean always provides an abundant food supply, but the narrow rock ledges have to be divided into the smallest possible "territories to provide nesting space for all and maintain the existence of the species. The cases of community nesting as in swallows may be explained in somewhat the same way or may, as it certainly does in the case of Rooks, involve the factor of mutual protection.

While the "territory" theory is the dominant theme of Mr. Howard's book he has much to say on other topics more or less related to it. In