( 143 ) 



WIND AND FLIGHT. 



BY 



F. W. HEADLEY, m.a., m.b.o.u. 



Part II. 



{Continued from page 121.) 



Advance without Movement of the Wings. 



A Gull sometimes advances at right angles to the wind 

 without beating his wings at all. Having attained some 

 slight altitude he will partly flex his wings and advance 

 rapidly, at the same time descending, till he almost touches 

 the ground or the sea. He will then turn and face the 

 wind, which will lift him till he attains his former 

 altitude. The wind increasing in velocity as he ascends, 

 aids him as it aids the lark to rise, only the lark beats his 

 wings instead of trusting to the wind entirely. Gulls 

 that are following a steamer may be seen advancing in 

 this way when the wind is blowing at right angles to the 

 ship's course. 



W 



n 



Fig. 4. — The upper line represents tlie course of the GruU's flight ; 

 W, the wind. 



Often they get help from an up-current. In their 



