. Birds in flight . oncentrated in the skeleton of the breast-bone andits shoulder-girdle, and the muscles attached thereto. Butthose who would inv^tigate the modifications of the rest ofthe body which have taken place in harmony with the require-ments of flight, must turn to more learned treatises. Thereis, however, one point which demands notice here. And thisis the popular belief that birds have the power of materiallyreducing their weight when on the wing by drawing air intotheir lungs, and storing it in large air-chambers enclosedwithin the body. These chambers are indeed concerned withth
. Birds in flight . oncentrated in the skeleton of the breast-bone andits shoulder-girdle, and the muscles attached thereto. Butthose who would inv^tigate the modifications of the rest ofthe body which have taken place in harmony with the require-ments of flight, must turn to more learned treatises. Thereis, however, one point which demands notice here. And thisis the popular belief that birds have the power of materiallyreducing their weight when on the wing by drawing air intotheir lungs, and storing it in large air-chambers enclosedwithin the body. These chambers are indeed concerned withthe needs of flight. But the precise part they play is yet tobe discovered. They certainly have no effect of renderingthe body lighter. So far as our knowledge goes it wouldseem that they act as regvdators of the temperature and asreservoirs of breathing air, during the strenuous efforts offlight. It is a mistake to suppose that it is unnecessary to con-sider other kinds of flight when studying that of birds,» Even 6. those who are not interested in the abstruse problems of themechanism of birds flight, will find that comparisons madebetween birds, bats, butterflies, and beetles when on thewing are immensely interesting, and help to bring out thepeculiarities of each. During the twilight hours of a still summer evening onemay compare, with advantage, the rushing swoop of thescreaming swift, borne with lightning speed upon long,ribbon-like pinions, with the curiously erratic flight of thewoolly bat with beaded eyes, who has ventured abroad forhis evening meal. One cannot but feel astonishment at themarvellous dexterity with which he twists and turns, nowshooting up into the sky, now darting downward. Whatbird can beat him, or even match him, in the art of doublingback on his tracks ? And one can put his skill at lightningturns to the test if one attempts to catch him in a butterflynet. Often indeed have I attempted this feat, but never yetwith success. In the glare of noon-day th
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbirds, bookyear1922
