ON THE POSITIONS ASSUMED BY BIRDS IN FLIGHT.1 [With 8 plates.] By BENTLEY BEETHAM, F. Z. S. I. STARTING. The flight of birds must ever remain a source of interest and inspiration to man, for should he eventually master aerial as successfully 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 ornithologist or the aviator, the actions of these naturally equipped performers 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 observation. 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 improbable, 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 combination 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 1 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 |