The migration of birds would appear miraculous, did we not know their extraordinary power of flight. Speaking of this, Bewick says—“If we can suppose a bird to go at the rate of only half a mile in a minute, for the space of twenty-four hours, it will have gone over, in that time, an extent of more than seven hundred miles, which is sufficient to account for almost the longest migration; but, if aided by a favourable current of air, there is reason to suppose that the same journey may be performed in a much shorter space of time. To these observations we may add, that the sight of birds is peculiarly quick and piercing; and from the advantage they possess in being raised to considerable heights in the air, they are enabled, with a sagacity peculiar to instinctive knowledge, to discover the route they are to take, from the appearance of the atmosphere, the clouds, the direction of the winds, and other causes; so that, without having recourse to improbable modes, it is easy to conceive, from the velocity of their speed alone, that most birds may transport themselves to countries lying at great distances, and across vast tracts of ocean.” * * * * * In speaking of the flight of birds, Mr. Rennie says—“Their capability of performing flights much longer than there is any necessity for supposing, may be proved by numerous facts. Even a sparrow has been calculated to fly at the rate of not less than thirty miles an hour, and many experiments prove that the eider duck can fly ninety miles in the same time. The common kite (_falco milvus_) has been observed to pass, without great exertion, over a space of a quarter of a league, in a minute; and it could fly, with ease, from Cape Pruth to the Land’s End, in a single day. M. Audubon, the distinguished ornithologist, has shot the passenger pigeon of America, and on dissection, found its stomach full of fresh rice, which, to have resisted the digestive process, must have been swallowed _not many hours_ preceding its death, but could not have been obtained within eight hundred miles of the place where it was killed. Though the nightingale, the willow-wren, and other birds of passage, fly with only half the swiftness, they may easily arrive in most parts of the south of Europe, or the north of Africa, in a few days.”—_Bewick_—_Rennie_—_Montagu._ BIRD, _v. obs._ To catch birds. BIRDBOLT, _s._ A small arrow with three heads, which was anciently discharged at birds from a cross-bow. BIRD-CATCHER, _s._ One that makes it his employment to take birds. BIRD-CATCHING, _s._ The act of taking birds or wild fowl, whether for food, for the pleasure of their song, or for their destruction, as being pernicious to the husbandman, &c. The methods are by birdlime, nets, decoys, &c. See BIRDLIME, DECOYS, NETS, &c.