176 



BIRD WORLD. 



his wings. On the end of the wing are the long 

 primary feathers, Hke the fingers of our hand. These 

 and the secondaries close to them form a strong web 

 which the bird can hold out at full length or bend 

 at the elbow. The whole wing is joined to the body 

 at the shoulder in such a way that the wing moves 

 forward and down, not straight up and down. It is 



Fig. 38. — Tail of Snowbird. 



Fig. 39. — Tail of Snowbird. 



this forward motion which pushes the bird along, and 

 the downward stroke which keeps him from falling. 

 Some birds — Kingbirds, for example — take rapid 

 strokes, so that they fly in a straight line without 

 falling between the strokes. Woodpeckers, on the 

 other hand, fall some distance between each stroke, 

 so that their flight is a succession of curves. 



The length of a bird's wing is important to notice. 

 A long, narrow wing gives a more jDOwerful sweep 



