But, to return to the pigeon, supposing it is possible for it to find its way, how long do you suppose it will take to get there ?" "It is estimated that birds of passage fly over two hundred miles a day, if they keep on the wing for six hours." "Two hundred miles in six hours is fast sailing, anyhow." "Swallows have been seen in Senegal on the 9th of October, that is, eight or nine days after they leave Europe; and that journey they repeat every year." "They must surely make some preparations for such a lengthy excursion." "When the period of departure approaches, they collect together in troops on the chimneys or roofs of houses, and on the tops of trees.
During this operation, they keep up an incessant cry, which brings families of them from all quarters.

The young ones try the strength of their wings under the eyes of the parents.

Finally, they make some strategic dispositions, and elect a chief." "You talk of the swallows as if they were an army preparing for battle, with flags flying, trumpets sounding, and ready to march at the word of command." "The resemblance between flocks of birds and serried masses of men in martial array is striking.

Wild ducks, swans, and cranes fly in a kind of regimental order; their battalions assume the form of a triangle or wedge, so as to cut through the air with greater facility, and diminish the resistance it presents to their flight.
"But how do you know it is for that ?" "What else could it be for?
The leader gives notice, by a peculiar cry, of the route it is about to take.

This cry is repeated by the flock, as if to say that they will follow, and keep the direction indicated.