Why Does My Bird Grind its Beak?
Often when birds are about to fall asleep they gently move their upper and lower beaks in a side to side motion which produces a raspy sound. This is a behavior that should not be confused with teeth grinding in humans which is a sign of stress. To the contrary, when you hear your parrot grinding its beak, this is evidence of a comfortable, relaxed parrot!
Some people think that this behavior is intended to keep a bird's beak trimmed. Although, to some extent it likely has this effect, other experts believe it to be just a self-soothing action and a sign of contentment.