250 THE HISTORY OF ANIMALS. [u. IT. 



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 pre- 

 served ; 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 swilt, which, some persons call cypsellus, resem- 

 bles 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 dis- 

 position. It flies against the goats and sucks them, whence 

 its name (aegothelas, 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. 



1. THERE are several kinds of eagles. One which is called 

 pygargus (hen-harrier), which is found in plains and groves. 



