1. The cuckoo, as it has been already observed, makes no nest, but lays its eggs in the nests of other birds, especially in that of the phaps, and in those of the sparrow and lark on the ground, and in the nest of the chloris in trees. It lays one egg, upon which it does not sit, but the bird in whose nest it lays both hatches the egg and nurses the young bird; and, as they say, when the young cuckoo grows, it ejects the other young birds, which thus perish. 2. Others say that the mother bird kills them, and feeds the young cuckoo with them; for the beauty of the young cuckoo makes her despise her own offspring. People assert that they have been eye-witnesses of most of these circumstances, but all are not equally agreed as to the mode in which the other young birds perish. Some persons say that the old cuckoo comes and devours the young of the other bird. Others say that the great size of the young cuckoo enables it to seize upon the food which is brought to the nest, so that the rest perish from starvation. Others say that the cuckoo, being the stronger bird, kills those that are brought up with it. 3. The cuckoo appears to act prudently in thus depositing her egg; for it is conscious of its own timidity, and that it cannot defend its young, and therefore places them under the protection of another bird, in order that they may be preserved; for this bird is very cowardly, and when it is pecked by even small birds, it flies away from them. CHAPTER XXI. 1. That the swift, which some persons call cypsellus, resembles the swallow, has been already observed, and it is not easy to distinguish them apart, except that the legs of the apos are covered with feathers. These birds rear their young in small nests made of mud, which have a passage sufficient for their admission. The nest is constructed in a narrow place under rocks and caverns, so that it avoids both beasts and men. 2. The goatsucker, as it is called, is a mountain bird, larger than the blackbird, and less than the cuckoo. It lays two, or not more than three eggs, and is slothful in its disposition. It flies against the goats and sucks them, whence its name (ægothelas, the goat-sucker). They say that when the udder has been sucked that it gives no more milk, and that the goat becomes blind. This bird is not quick sighted by day, but sees well at night. 3. The ravens in small districts, and where they have not food enough, are found only in pairs; and as soon as their young birds are able to fly, the old birds first of all turn them out of the nest, and then drive them from the place. The raven lays four or five eggs. When the hired soldiers of Medias perished in Pharsalus, Athens and the Peloponnesus were deserted by the ravens, as if they had some means of communication with each other. CHAPTER XXII.