It is because his feet move on, but his head stays still.

这是因为他的脚动了，而他的头保持着静止。

They use them for specialized feeding in wetlands, for preening their hind feathers, and for helping their heads stay level as they walk and fly.

他们用它们在湿地进行专门的喂养，整理后羽毛， 并在行走和飞行时帮助头部保持水平。

He was a wizard of the Royal Court. They tried to behead him but, for some strange reason, his head stayed connected to his body through a thread.

他是宫廷里的巫师，他们想要砍他的头，但由于某种奇怪的原因，他的头通过一根线和他的身体连在一起。