LAND BIRDS 295 



The sharp-shinned hawk is small (length, 11 J inches), with a long square 

 tail marked by widely separated dark bands across it, the widest one 

 nearest the end. The principal food is song birds, so this hawk should be 

 destroyed wherever found. Cooper's hawk is dark brown with grayish and 

 brownish spotted under parts. Its tail is round. In food habits it is much 

 like the sharp-shinned hawk, and it should be destroyed. 



The red-tailed hawk (Fig. 241), more often called the chicken-hawk, is 

 a great destroyer of injurious mammals. Poultry and other birds do not 

 constitute 10 per cent, of this hawk's food, and all other beneficial animals 

 which it eats added do not make 15 per cent. So its record is 85 per cent, 

 as a friend, against 15 per cent, as an enemy, of the farmer. 



Fig. 241. Red-tailed hawk (much reduced). Length, 21 inches. (Bulle- 

 tin 17, Biological Survey, 1902.) 



Owls in America north of Mexico number eighteen species. " They vary 

 in size from the tiny elf-owl of Arizona (only 6 inches long) to the great gray 

 owl of the Arctic regions (30 inches long). The owls (Fig. 242) (Bubon'idce 

 and Strig'idce) have a soft plumage, hence their silent flight. Their eyes are 

 large and dilatable, enabling them to see well at night. The face is so 

 broad that both eyes look forward. They are immovable, so that to look 

 in another direction the head must be turned. They have a peculiar voice, 

 a screech in our little screech owl and a " who-hoo-whoo " in the great 

 horned owl. When one is camping in the woods the sound of this bird 

 gives one queer creepy feelings until one knows what is making it. Owls 

 live chiefly on rats, mice, frogs, snakes, and rabbits. Some of the smaller 



