. British birds. Birds. POSITIONS ASSUMED BY BIRDS IN FLIGHT. 201 when flight is being executed amid tumultuous currents. But this method of steering by the tail is rather corrective than initiative in its use, being principally employed to compensate for irregularities in the air-currents. WHien a bird is suddenly and deliberately changing the direc- tion of its courseâturning an aerial corner, so to speakââ the plane of the wings is changed from the horizontal position assumed when gliding to a more or less vertical position, the inclination depending on the abruptness of the turn and the pa
. British birds. Birds. POSITIONS ASSUMED BY BIRDS IN FLIGHT. 201 when flight is being executed amid tumultuous currents. But this method of steering by the tail is rather corrective than initiative in its use, being principally employed to compensate for irregularities in the air-currents. WHien a bird is suddenly and deliberately changing the direc- tion of its courseâturning an aerial corner, so to speakââ the plane of the wings is changed from the horizontal position assumed when gliding to a more or less vertical position, the inclination depending on the abruptness of the turn and the pace at which it is executed. If the burn is to the right, then the left wing is raised and the. FIGURE 4.âTHE DEPRESSED TAIL USED AS A BRAKE. [Photographed by Bentley Beetham). right depressed, and, of course, vice versa for a turn to the left. When writing here of one wing being raised and the other depressed, I refer to their positions relative to each other, and not to their relation with the body. That is to say, the wings and body may be held rigidly in one plane, the inclination of this as a whole being changed from the horizontal to towards the vertical. This vertical position has been almost reached by the bird, of which, unfor- tunately, only a portion is shown, in the upper part of Figure 5. It will be noticed that the left wing is depressed. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original London, Witherby & Co
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Photo credit: © Library Book Collection / Alamy / Afripics
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherl, booksubjectbirds
