Who needs to be told that birds fly? So common-place has this fact become that the many, and varied forms of wings, and the peculiarities of flight which are associated with these differences, are rarely perceived. Even sculptors, and artists show a hopeless unfamiliarity with the shapes of wings, and their meanings, at any rate, as a general rule. Look at their attempts to display birds in flight, or in the fanciful use of wings which convention has ascribed to angels. For the most part these superbly beautiful appendages are atrociously rendered. Yet it must be confessed that any attempt to explain exactly how birds fly must fail. We can do no more than state the more obvious factors which are indispensable to flight, and the nature of its mechanism. The subtleties, and delicate adjustments of actual flight evade us. Our appreciation, however, of this supreme mode of locomotion will be materially quickened, if we make a point of studying the varied forms of flight as opportunities present themselves. To begin with, it is worth noting that the size of the wing decreases with the weight of the body to be lifted--up to a certain point, of course. This, perhaps, may seem strange a statement to make. But it can be readily verified. Compare, for example, the size of the body in relation to the wings, in the case of the butterfly and the dragon-fly, on the one hand, and the partridge and the crow, on the other. The two first named, by comparison, have enormous wings. Birds, it will be noticed, which haunt woods, or thickets, have short, rounded wings, like the wren, the pheasant, or the tawny owl. Such, on the other hand, as live in the open, like the gull, and the swallow, have long, pointed wings. The reason for this is fairly plain. Birds which must steer their course through the intricate mazes of a wood, or thicket, would find their flight seriously hampered by long wings. [Illustration: _Pheasants_] These general principles once realized, a foundation is laid on which one may base observations on the peculiarities of flight distinguishing different types of birds.