Of the vultures, the black ones are the strongest. No person has yet found a vulture’s nest: so that some have thought, though erroneously, that these birds come from the opposite hemisphere. The fact is, that they build their nest upon the very highest rocks; their young ones are often to be seen, generally two in number. Umbricius, the most skilful among the aruspices of our time, says that the vulture lays three eggs, and that with one of these it purifies the others and its nest, and then throws it away: he states also that they hover about for three days, over the spot where carcasses are about to be found. We find no less than sixteen kinds of hawks mentioned; among these are the ægithus, which is lame of one leg, and is looked upon as the most favorable omen for the augurs on the occasion of a marriage, or in matters connected with property in the shape of cattle. There is a Roman family that has taken its surname from the species known as the “buteo,” from the circumstance of this bird having given a favorable omen by settling upon the ship of one of them when he held a command. The Greeks call one kind “epileus;” the only one that is seen at all seasons of the year, the others taking their departure in the winter. The various kinds are distinguished by the avidity and the various methods with which they seize their prey; for while some will pounce on a bird only on the ground, others will seize it only while hovering round the trees; others, again, while it is perched aloft, and others while it is flying in mid-air. Pigeons, on seeing them, are aware of the nature of the danger to which they are exposed, and either settle on the ground or else fly upwards, instinctively protecting themselves by taking due precautions against their natural propensities. In the part of Thrace which lies above Amphipolis, men and hawks go in pursuit of prey, in a sort of partnership; for while the men drive the birds from out of the woods and the reed-beds, the hawks bring them down as they fly; and after they have taken the game, the fowlers share it with them. It has been said, that when sent aloft, they will pick out the birds that are wanted, and that when the opportune moment for taking them has come, they invite the fowler to seize the opportunity by their cries and their peculiar mode of flying. Hawks will not eat the heart of a bird. The night-hawk is called cybindis; it is rarely found, even in the woods, and in the day-time its sight is not good; it wages war to the death with the eagle, and they are often to be found clasped in each other’s talons. [Illustration: GROUP OF FALCONS.]