"Perhaps it may not be amiss to make an estimate of the number of Pigeons contained in such a host, and of the amount of food consumed by them. Granting the procession to be a mile broad, which is certainly no exaggeration, and that at a given speed it travels for three hours, we obtain a parallelogram of eighteen square miles, English measure; this, reckoning only two pigeons to the square yard, would give 1,000,115,736,000 individuals in such a flight; and if each Pigeon required daily half a pint of food, the whole multitude would consume 8,712,000 bushels daily. Wilson makes a similar calculation, and arrives at the conclusion that one swarm contains more than 2,000,000,000,000 Pigeons, and requires daily 17,424,000 bushels of corn. "As soon as the Pigeons discover a sufficiency of food to entice them to alight, they fly round in circles, reviewing the country below. During their evolutions on such occasions, the dense mass which they form exhibits a beautiful appearance as it changes its direction, now displaying a glistening sheet of azure, when the backs of the birds come simultaneously into view, and anon suddenly presenting a mass of rich deep purple. They then pass lower over the woods, and for a moment are lost among the foliage, but again emerge and are seen gliding aloft. They now alight, but the next moment, as if suddenly alarmed, take flight, producing by the flapping of their wings a noise like the roar of distant thunder, and sweep through the forests to see if danger is near. Hunger, however, soon brings them to the ground. When alighted, they are seen industriously throwing up the dead leaves in quest of the fallen mast. The rear ranks are continually rising, passing over the main body, and alighting in front in such rapid succession that the whole flock seems still on the wing. The quantity of ground thus swept is astonishing, and so completely has it been cleared that the gleaner who might follow in their rear would find his labour completely lost. Whilst feeding, their avidity is at times so great that, in attempting to swallow a large acorn or nut, they are seen gaping for a long while as if in the agonies of suffocation. "On such occasions, when the woods are filled with these Pigeons, they are killed in immense numbers, although no apparent diminution ensues. About the middle of the day, after their repast is finished, they settle on the trees to enjoy rest and digest their food. On the ground they walk with ease, as well as on the branches, frequently jerking their beautiful tail, and moving the neck backwards and forwards in the most graceful manner. As the sun begins to sink beneath the horizon, they depart _en masse_ for the roosting-place, which not unfrequently is hundreds of miles distant, as has been ascertained by persons who have kept an account of their arrival and departure.