220 THE STRUCTURE AND LIFE OF BIRDS chap. 



winging their way quite unconscious of cameras, and 

 sensitive plates, and fame. On the other hand, Mr. 

 Muybridge's American Eagle, with his somewhat 

 draggled plumes, looks like a scared captive, conscious 

 that the camera is being aimed at him. However, it 

 is only under conditions like these last, that photo- 

 graphs such as those of Professor Marey, showing the 

 position of the wing at every stage, can be obtained. 



When the bird is flying with great energy, he raises 

 his wings high till in some cases they touch one 

 another, and this is the cause of the slapping noise 

 that we hear when a Pigeon rises from the ground. 

 The wing next moves forward and downward, its 

 under surface looking backwards and downwards. In 

 its forward movement it meets with little resistance, 

 since it cuts edgeways through the air. When it can 

 strain no further forward and down, it is drawn back- 

 ward and bent sharply at the wrist-joint, facing during 

 the process forwards and downwards. During the last 

 period of the upstroke there is a further turn, and it 

 moves edgeways forward. 1 This description of the 

 movements of the wing refers to very vigorous flight, 

 such as we most commonly see when the bird is 

 getting up steam. When he has plenty of way on 

 there is no need for him to take these very long and 

 exhausting strokes, unless, like the Duck, he is one 

 of those that seem always to fly with effort. In birds 

 of long flight, the wing does not rise very high or 

 descend very low, and it is flexed very little, if at all, 

 when it is raised. These points can be made out if a 

 Gull is watched when it is flying steadily. In some of 

 1 Further details under next heading. 



