22 



Fic;. 23 A young owl. The owl 1mm s at yilght. 

 What do you notice about tl?e size of its pupils? 

 How does this help the owl? (American mu- 

 seum OF NATURAL HISTORY — OVERTON) 



Kic. 24 The American eagle. In which way is it 

 fitted for obtaining food? (nature magazine — 

 fisher) 



ll?c Living Things of the Earth unit i 



strong and attached far back enabling 

 them to exert a powerful push against 

 the water. The position of the legs 

 makes it easy for them to tip their 

 heads down for a dive. Their feet are 

 large and webbed. 



Water birds all produce much oil 

 which protects their feathers from get- 

 ting wet. This fact has given rise to the 

 common expression, "as water rolls off 

 a duck's back." 



Birds which cannot fly. A few species 

 live wholly on land and never fly. The 

 ostrich, the largest living bird, and its 

 less familiar relatives have ^\'ings which 

 are too small to be of any use. But all 

 are good runners, running as fast as 

 sixty miles an hour. When attacked and 

 cornered, an ostrich defends itself by 

 means of a kick which is dangerous to 

 man. 



Perching birds. These, for the most 

 part, are the birds that sing. You may 

 kno\\' best the house (English) sparrows 

 and the starlings of our crowded cities; 

 the robins and the bluebirds of our 

 suburbs; or the swallows and the crows 

 of the countryside. These, and about 

 four hundred fift\- other species, are 

 perching birds. They are the birds to 

 which man omcs much thanks for keep- 

 ini^- down insect pests and for eating the 

 seeds of weeds that would spoil crops 

 and gardens. The songbirds often steal 

 our fruit, but their bill of fare consists 

 largely of insects or seeds of weeds 

 that are harmful to man. 



Migration of birds. Many birds and 

 some other animals migrate. They move 

 from one place to another and back 

 airain in tlie course of a year. The 

 migrating season is generally the spring 



