Page:The Zoologist, 4th series, vol 1 (1897).djvu/135

Rh neck. The neck vibrates sinuously, but the head remains steady, thus enabling the bird, even at top speed, to look around with unshaken glance in any direction. The wings lie along the sides about on a level with, or a little higher than, the back, and are held loosely just free of the plunging "thigh." There is no attempt to hold them extended, or to derive any assistance from them as organs of flight. Indeed, I doubt whether the conformation of the wings permits their being held out to any extent with the edge to the front; and the front edge is thickly and heavily covered with long feathers (which are regularly plucked for the market). In fact, it may be said that the wings assume just that position along the sides which the wind would force them into when the Ostrich is running at a great pace; their position is exactly that which offers least resistance to the passing wind.

When Ostriches are startled, as by a dog; when they start away to run; or when not very hard pressed, they will often run, and very rapidly, for some distance with their wings raised nearly upright on each side of the neck; just as, under similar conditions, Springbucks will run with the white fan on their backs raised, frequently "pronking." When the Ostrich runs thus, with its wings raised, it generally moves with a high, springy, bounding step, never with the long raking stride of the bird that, hard-pressed, is fleeing for its life. Raised wings are undoubtedly an obstacle to the greatest pace. So the Springbuck, when he stretches himself out to run his fastest, shuts down his fan, as the attitude which enables him to expand it prevents his attaining to his greatest pace. When an Ostrich, after a long run, is very tired, its wings sometimes droop; this is due to exhaustion; they are never, by a running bird exerting itself to the utmost, held out away from the sides to lighten its weight or to increase its pace. But the wings appear to be of great service in turning, enabling the bird to double abruptly even when going at top speed.