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a, clambering foot of chimney sweep; b, climbing foot of woodpecker; c, perching foot of thrush; d, seizing foot of hawk; e, scratching foot of pheasant; f, stalking foot of kingfisher; g, running foot of ostrich; h, wading foot of heron; i, paddling foot of gull; k, swimming foot of duck; l, steering foot of cormorant; m, diving foot of grebe; n, skimming foot of coot. Question: Does any bird use its foot as a hand? (Fig. 320.)

Flying.—When studying the quill feathers of the wing, you saw that the wider side of the vane is beneath the feather next behind it. During the downward stroke of the wing this side of the vane is pressed by the air against the feather above it and the air cannot pass through the wing. As the wing is raised the vanes separate and the air passes through. The convex upper surface of the wing also prevents the wing from catching air as it is raised. Spread a wing and blow strongly against