Most of us, probably, at one time or another, in taking a walk through the woods, have been startled, almost out of our wits, by a sudden "whirr" of wings at our very feet; made by some crouching pheasant, waiting till the very last moment before revealing himself, by taking flight. This alarming noise is due to the shortness and stiffness of the quill, or flight-feathers. With pinions moving with incredible speed, the bird is off like a rocket. Not seldom, probably, it owes its life to this ability to disconcert its enemies, till it has put a safe distance between itself and danger. By way of contrast, let us take the absolutely silent, easy movements of the owl, stealing forth in the twilight of a summer's evening, seeking whom he may devour. Here, again, we have a meaning in the mode of flight. Here silence is more than golden: it means life itself. Nimble-footed, sharp-eared mice and rats, must be snatched up before even the breath of suspicion can reach them. The uncanny silence of this approach is rendered possible, only by what may be called a "muffling" of the wings. For the flight-feathers are not only of great breadth, but they are covered, as it were, with velvet-pile, the "barbules" of the wing-quills, which form the agents by which the "web" of the quill is held together, having their upper spurs produced into long, thread-like processes, which extinguishes any possibility of a warning "swish." John Bright, in one of his magnificent perorations, caused his spell-bound listeners to catch their breath, when, conjuring up a vision of the Angel of Death, he remarked "we can almost hear the rustle of his wings." One realizes the vividness of that imagery, when one hears, as on rare occasions one may, the awe-inspiring rustle of the death-dealing swoop of the falcon, or the sparrow-hawk, as he strikes down his victim. But the swish, and whistle of wings often stirs the blood with delicious excitement, as, when one is out on some cold, dark night, "flighting." That is to say, awaiting mallard passing overhead on the way to their feeding ground, or in watching the hordes of starlings, or swallows, settling down to roost in a reed-bed. No words can describe these sounds, but those to whom they are familiar know well the thrill of enjoyment they beget. There is no need, here, to muffle the sound of the wing-beat. The falcon vies with the lightning in his speed, escape is well nigh hopeless: neither have the swallows need for silence; indeed, on these occasions, they add, to the music of their wings, the enchantment of their twittering. So much for flight in its more general aspects. Let us turn now to a survey of some of the more remarkable forms of flight, beginning with that known as "soaring."