A perch. Soaring birds cannot by any possibility begin flight unless there is such a movement to change from a position of rest to one of motion. _Fig. 9. Wing Movement in Flight. _ In the diagram therefore the bird in moving forwardly while raising the wing upwardly depresses the rear edge of the wing as in position 1 and when the wing beats downwardly the rear margin is raised in relation to its front margin as shown in position 2. A WEDGING MOTION. --Thus the bird by a wedge-like motion gives... read more
