ON THE POSITIONS ASSUMED BY BIRDS IN FLIGHT. 1 



[With 8 plates.] 



Ey Bentley Beetham, F. Z. S. 



-STARTING. 



The flight of birds must ever remain a source of interest and 

 inspiration to man, for should he eventually master aerial as suc- 

 cessfully as he has terrestrial locomotion, birds would, by reason 

 of their inherent sensibility to gauge the varying aircurrents, still 

 remain vastly his superior in the art, if not in actual pace at least 

 in the finer manipulations. 



But whether we regard flight from the standpoint of the ornitholo- 

 gist or the aviator, the actions of these naturally equipped per- 

 formers can not be too closely regarded. 



The great difficulty met with in studying the flight of birds is the 

 indefinite and almost inexpressible nature of much of our observa- 

 tion. We see a bird make a sudden turn or falter in its course; a 

 little thing, yet even if we could analyze its actions, which is improb- 

 able, it would take a page or two of writing before we could be sure 

 that another would understand the positions and actions as we saw 

 them. In our present lack of intimacy with the subject words are 

 quite inefficient, and we must largely rely on pictures, photographs 

 by preference, wherewith to record our observations. 



The slower and individual movements of the wings and tails of 

 such large birds as herons, gulls, or eagles, are easy to perceive, and 

 in many cases their object or result can be appreciated, if only one 

 can get close enough. Unfortunately, however, our near glimpses 

 of large birds on the wing are usually but momentary, and it is only 

 by piecing together little isolated scraps of observation that we can 

 get a consecutive idea of what has taken place. Often the combina- 

 tion of our eyes and brain is far too slow to analyze and follow the 

 different movements, and the only impression the mind receives is one 

 of rapid beating motion, as is so noticeable in the flight of bees and 



i Reprinted by permission from British Birds, Witherby &*Co., London, vol. 4, June, 1910-May, 1911, PP. 

 162-168, 198-203,350-356. 



38734°— sm 1911 28 433 



