FLIGHT OFBIRDS. 19 



single file, either in a straight line or in the form of 

 the letter V. 



To the student of Ornithology, the flight of birds, 

 and the motion of the wings peculiar to the different 

 tribes, will form an interesting subject for observa- 

 tion. To the practised eye, this is quite a sure indi- 

 cation of the class to which the bird belongs. 



By those who are familiar with the easy and unre- 

 strained flight of the Eagle, he is at once recognized. 

 Now he soars in graceful curves at an immense height, 

 as though intent on viewing the whole earth beneath 

 him, — then with unmoving wing glides in a horizontal 

 course until lost in the deep blue vault of Heaven. 

 The motions of the Turkey Vulture are also of a most 

 singular and interesting character. These birds may 

 often be seen sailing overhead for hours together, 

 moving in curves or gently undulating lines, rising 

 and falling at pleasure, with but little apparent mo- 

 tion of the wings, and sometimes ascending in easy 

 circles beyond the reach of vision. 



The Woodpecker describes, in its course through 

 the air, a waving line, which is in consequence of 

 the wings being alternately closed and expanded at 

 intervals during flight. The Sparrows also perform 

 a zigzag course, rising and falling first to the one side 

 and then to the other. In the Fly-catchers the mo- 

 tion of the wings is rapid and steady; sometimes in 

 long-continued flight their course is slightly undula- 

 ting. The Humming Bird darts with the swiftness 

 of an arrow, and the vibrations of its wings are so 

 incessant as to render them almost invisible; while 



