202 



A COUNTRY READER, 



chaffinch flies in an up and down motion. A 

 starling flies quite straight. A swift and swallow 



glide and curve. 

 A peewit swoops 

 and jerks. A kes- 

 trel hawk hovers 

 and drops sud- 

 denly. An owl 

 flies and drops of 

 a night on a 

 mouse from a 

 great height with- 

 out the slightest 

 noise. And so on 

 throughout the 

 list of birds. 



The air is full 

 of currents and 

 cross currents, up 

 and down cur- 

 rents, currents 

 differing in their 

 degrees of heat 



o 



and cold, and dif- 

 fering also in their 

 degree of velocity or speed. 



The birds seem instinctively to know how 

 best to save their powers of flight by taking- 

 advantage of these various air currents. 



