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.