CHAPTER IV. 

 STARTING. 



THE PRELIMINARY JUMP LOSS OF ALTITUDE BETWEEN WING- 

 STROKES — THE WING'S FREEDOM TO ROTATE AEROPLANES 



MUSCLES BIG BIRDS AND SMALL. 



The Preliminary Jump. 



I have shown how a bird when flying maintains 

 and propels himself, when we have given him in 

 imagination a good start. We have now to study 

 his method of starting. 



Let us suppose that he is standing on the ground ; 

 if he is to fly he must somehow get clear of it. For 

 this purpose his long, strong legs are of great service 

 to him ; it is owing to them that he is so good a 

 starter. Such is the bird that I think of as typical. 

 Not only are his legs strong, but they are long, 

 unless we compare them with those of a Wader or 

 a Heron, birds that for their particular mode of 

 life have developed an inordinate length of leg. 

 The Puffin and the Swift, by their helplessness on 

 level ground, call attention to the remarkable leg- 

 power of the ordinary small bird, or bird of moderate 

 size. The Swift and the Puffin cannot take the 

 preliminary jump with which flight must begin. 

 Bulky, short-legged birds all rise with difficulty ; 

 the jump that should in a moment obtain for them 

 freedom of wing action is beyond their power. 



