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304 



ANIMAL MOVEMENT 



Some birds are able to stop quite suddenly, and turn with 

 great rapidity. When a Pigeon does this its body assumes a 

 vertical position, and the tail is fully spread out. In this way a 

 maximum resistance to further onward progress is brought into 

 play. It is possible that the bastard- wing may give some help 

 in stopping and turning movements, but further investigation is 

 needed before we can feel certain as to the part it plays in flight. 



Powerful and rapid flight is commonly correlated w'th great 



Fig. 836. — Instantaneous Photographs of Phases in Flight. The upper figure gives deliberate flight of a Gull 

 [read from right to left), and the lower shows the rapid flight of a Pigeon (read from left to right). The photographs 

 were taken at very short intervals in the latter case, and therefore overlap. 



expanse of wing, but the flying possibilities of any particular 

 bird depend upon many other things besides this. For instance, 

 the shape of the wings is of importance. In expert flyers they 

 are usually long and pointed, as may be seen to perfection in 

 Swallows and Swifts. But short wings moved with great rapidity 

 may also be very effective. And it is sufficiently obvious that long- 

 distance flying and rapid flight for a short time are likely to be 

 associated with arrangements of somewhat different kind. 



There appears to be a dearth of accurate observations re- 

 garding the speed of various birds, especially the average that can 

 be maintained for long distances. But it appears that 60 miles an 



