They start slow, but soon the combination of the  bird's aerodynamic body, swept back wing shape, and powerful muscles work together to  turn this bird into a feathery missile.

它们起步缓慢，但很快，鸟的空气动力学身体、后掠翼形状和强大的肌肉共同作用，将这只鸟变成了羽毛状的导弹。