182 THE HUMAN SHDE OF BIRDS 



tail serves as a rudder, and is bent somewhat in an 

 upward direction while the bird is rising, and in a 

 downward one in its descent; in turning it takes 

 a slanting position. When soaring or circling, the 

 tail alone directs the course of flight, while the posi- 

 tion of the apparently motionless wings determines 

 the greater or less rapidity of the same. The rela- 

 tive rapidity and the nature of the flight is in per- 

 fect harmony with the formation of the wing and 

 the construction of the feathers. All birds pos- 

 sessing long, narrow, sharp-pointed wings and close, 

 smooth plumage are rapid fliers in a straight line, 

 though imable to diverge from their course with the 

 same quickness as birds with shorter and rounder 

 wings. With the faster fliers the wings overlap 

 the tail, while with those which can turn quickly the 

 tail generally exceeds the wings in length. Good 

 fliers often have the tail forked, although the con- 

 trary sometimes occurs when the tail has long centre 

 feathers. Large, broad, rounded wings are weU 

 adapted for rising, and for long and easy soaring 

 at great elevations; but they render descent diffi- 

 cult. Those birds, however, which carry pointed 

 wings can rush with them half expanded from a 

 considerable height. Short round wings render 

 flight more difficult, and make it necessary to use 

 very rapid and strong strokes. The greater or less 



