Originally published in The Leisure Hour (Religious Tract Society) vol.1 #15 (08 Apr 1852).
Swallows fly in the form of a wedge. The leading of the group is confided to a chief, who takes his station at the apex. He yields to another when tired, and goes to the end of one of the lines. It is observed that old and young birds fly in separate companies; and that the old ones return to the place whence they set out, while the young do not. Males and females fly in separate lines, though in the same company. Birds which differ in voice also keep separate lines during their migratory flights. In a flight of bullfinches, for instance, all those having a deep-toned voice fly on one side, while those with high tones fly on the other: birdcatchers are acquainted with this fact. It becomes a question whether these birds are of the same species. It is possible that those with deep voices may have a flat skull, and the others a high one; if so, though the plumage may be the same, they are of different species; and, if put together, would probably not match. Birds generally migrate for the sake of food and climate. Some speculators have said it was from the relation between the magnetism of their bones and that of the earth!
As to the mode of progression, some birds run; others fly; others swim; others walk. Most of them fly; but the cassowary, ostrich, and penguin do not. There is also a rare European bird, called "the great hawk," which does not. Some seabirds become bewildered on land, and seem to lose the power of flight; so that they may be kept without cutting their wings, if distant from the sea. Poultry fly with difficulty; magpies and jays flutter, and fly slowly; pigeons flap their wings over their head; starlings swim in the air; the kingfisher goes like an arrow; small birds fly in jerks; sky-larks rise and fall perpendicularly; the wood-lark remains poised in the air; geese and cranes adopt figured flights; the cormorant glides over the sea.
The flight of some birds is very rapid. Birds of prey sometimes fly at the rate of sixty miles an hour. In 1828, an experiment was made, in London, with 56 carrier pigeons brought from Liege, and thrown up. One of them (Napoleon) flew the 300 miles in less than six hours; and most of them reached Liege within two hours afterwards. A hawk went 700 miles at 45 miles an hour. A hawk from Fontainbleau was found at Malta next day; and, as it never flies at night, its actual rate of progression, when on the wing, was probably more than 75 miles an hour. At New York, there have been killed birds having in their crops rice which they had obtained in Carolina; so that they had travelled three or four hundred miles in six hours. Their flight is sometimes much assisted by the wind; which, when blowing a hurricane, moves at the rate of from 80 to 100 miles an hour. Mr. Sadler declared that he once travelled in a balloon at the rate of 90 miles an hour, which shows how migratory birds may be carried along.