CHAPTER X. 1. This is the mode of the sexual intercourse of the partridge, and the way in which they are caught, and the nature of the rest of their crafty disposition. Quails, and partridges, and some other birds make their nest upon the ground, as it has been already observed. Of such birds the lark, woodcock, and quail do not perch upon trees, but upon the ground. 2. The woodpecker does not settle upon the ground, but it strikes trees in order to drive out the worms and flies which they contain, and it picks them up with its tongue as they emerge. Its tongue is wide and large. It walks upon the trees in any position, even beneath the branches, like the gecko. It has claws stronger than those of the colœus, which provide for its safety in climbing trees; for it fixes them in the bark as it walks up the trees. There is one kind of woodpecker less than the blackbird, covered with small red spots, and another kind larger than the blackbird, and a third kind nearly as large as the domestic hen. It builds its nest upon trees, as it has been already observed, both on olive and other trees; and it feeds upon ants and worms which live in trees. It hunts for worms so diligently that they say it hollows out the trees so much as to throw them down. A tame bird has been known to place an almond in a crack in wood, to prepare it for the stroke of its bill, and break it with three blows, in order to eat the kernel. CHAPTER XI. Many prudent actions appear to be performed by cranes; for they travel great distances, and fly at a great elevation, in order that they may see farther; and if they see clouds and wintry weather, they descend and rest themselves. They have also a leader in front; and in the rear are those which give a signal by whistling, so that their voice may be heard. When they settle on the ground, the rest sleep with their head under the wing, first on one foot, then on the other; but the leader watches with his neck stretched out, and when he sees anything he gives a signal by his cry. The pelicans, which inhabit the rivers, swallow large smooth shells with their drink, and when they have been digested in the first part of their stomach, they vomit them up, in order that they may pick out and eat their flesh when they open their valves. CHAPTER XII. 1. The habitations of wild birds are contrived with relation to their mode of life and the preservation of their young. Some of them are kind to their young and careful of them: others are of a different disposition. Some manage well in their mode of life: others do not. Some dwell in clefts, and holes, and in rocks, as the birds called charadrius. This bird is faulty both in its colours and its voice. It appears during the night, and escapes in the day time.