A tiny feathered "thumb," the alula, improves flight control. The protruding shaft on the first wing feather makes a loud, rustling sound—adding acoustics to the visual display.

微小的拇翼改善了对飞行的控制能力，第一翼羽上的凸出轴结构会发出沙沙的响声——在保持视觉效果的同时还增添了声学效果。

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A tiny feathered "thumb," the alula, improves flight control. The protruding shaft on the first wing feather makes a loud, rustling sound-adding acoustics to the visual display.

微小的拇翼改善了对飞行的控制能力，第一翼羽上的凸出轴结构会发出沙沙的响声——在保持视觉效果的同时还增添了声学效果。

youdao