The wing of the Swallow (Plate VIII.a) is pointed like that of the Peregrine Falcon, and is adapted for rapid flight. Both these birds secure their prey on the wing, and could not, therefore, live otherwise.
The wing of the Partridge is, on the contrary, rounded; this bird does not cut through the air, but can only raise itself in flight with rapid fluttering of the wings, and with a sudden loud “whirr” which makes considerable noise if the covey is a large one. The wing of the Partridge, therefore, is not at all adapted for enabling the bird to catch its prey flying, but only for moving from place to place, where it picks up its food walking.
From this we learn that the various kinds of wings correspond to various ways of flight and that each bird works out its destiny in its own way. It is suggestive of the organisation of an army, composed of cavalry, infantry, artillery, and other divisions. These also have different kinds of functions, which are necessary both
(a) SWALLOW’S WING; (b) THAT OF THE PARTRIDGE.
individually and in combination, and the one cannot supply the place of the other.