Chapter V.

1. The vulture builds its nest in inaccessible rocks, wherefore its nest and young ones are rarely seen. For this reason Herodorus, the father of Bryson the sophist, says that vultures come from another part of the earth, which is invisible to us, giving as a reason for his opinion, that they are seen in great numbers suddenly following the path of an army. But difficult as it is to observe them, their nests have been seen. The vulture produces two eggs. No other carnivorous bird has been observed to produce young more than once a year; but the swallow more frequently produces young twice a year than the carnivorous birds. If a person pierces the eyes of young swallows they recover, and are able to see afterwards.