These displays are not casual affairs in the ordinary course of the day's doings. It is a common thing for one of our birds to choose a particularly conspicuous spot, preferably on an elevated terrace, from which his display will carry farthest to the eyes of the crowd. Even if the bird were controlled by the will of a trainer for the purpose of vanity display, the exhibition could not possibly be more perfect. Like a good speaker on a rostrum, the bird faces first in one direction and then in another, and occasionally with a slow and stately movement it completely revolves on its axis for the benefit of those in the rear. "Vain as a peacock" is by no means an unjustifiable comparison. Plumage displays are indulged in by turkeys, the blue bird of paradise, the greater and lesser birds of paradise, the sage grouse and pinnated grouse, ruffed grouse, golden pheasant and argus pheasant. On the whole, we may fairly set down vanity as one of the well defined emotions in certain birds, and probably possessed by the males in many species which have not been provided by nature with the means to display it conspicuously. Materials for Study. In seeking means by which to study the mental and temperamental traits of wild birds and mammals, the definite and clearly cut manifestations are so few in kind that we are glad to seize upon everything available. Of the visible evidences, pugnacity and the fighting habit are valuable materials, because they are visible. Much can be learned from the fighting weakness or strength of animals and men. In our great collections of birds drawn from all the land areas of the globe, our bird men see much fighting. Mr. Crandall has prepared for me in a condensed form an illuminating collection of facts regarding PUGNACITY IN CAPTIVE BIRDS 1. Most species do more or less competitive fighting for nesting sites or mates, especially: Gallinaceous birds,--many of which fight furiously for mates; The Ruff, or Fighting Snipe (_Machetes pugnax_),--very pugnacious for mates; House Sparrows (_Passer domesticus_) fight for nesting places and mates; and Some Waterfowl, especially swans and geese, fight for nesting places. 2. Most species which do not depend chiefly upon concealment, fight fiercely in defense of nests or young. Typical examples are: Geese; Swans; The larger Flycatchers; Birds of prey, especially the more powerful ones, such as Bald Eagles, Duck Hawks and Horned Owls. 3. Some species fight in competition for food. Conspicuous examples are: The fiercer hawks; Some carrion eaters, as the King Vulture, Black, Sharp-Shinned, Cooper, Gos and Duck Hawks, which fight in the air over prey. 4. Certain birds show pugnacity in connection with the robber instinct, as: Bald Eagle, which robs the Osprey; Skua and Jaeger, which rob gulls. 5. Some species show general pugnacity. Species to be cited are: Cassowaries, Emus and Ostriches, all of which are more or less dangerous;