BIRDS OF PREY 25 1 



themselves away in hollow trees or old ruins, into W'hich the unwelcome 

 light cannot penetrate ; and it is not until some little time after sunset 

 that they make their appearance. Then through the hours of night 

 they hunt for prey, and can see their victims as clearly in the darkness 

 as hawks can in broad day-light. Now, it is evident enough that the 

 eyes of the owds must be very differently formed from those of the 

 hawks, for otherwise they w^ould be of no use at all after nightfall. 

 And, when we come to examine them, we find at once that such is the 

 ca-e. Not only are their eyes very large themselves, but, as you must 

 have noticed, they are surrounded by a kind of circular ring, sometimes 

 composed of white feathers and sometimes of browai. 



THE SECRETARY BIRD 



If the thick plumage of the owl's head were all set In the usual 

 manner, the feathers would project so far in front of the eyes that the 

 bird would have scarcely any range of sight. But the curious feathery 

 circle which surrounds the owl's eyes serves as a narrow slit in a deep 

 window casing, and enables it to see in all directions ; so that, without 

 moving its head, it is able to keep watch over a very large extent of 

 country. 



In other parts of their struc/in-e I'ne owls are not at all unlike th>? 



