This proverb means that it is foolish to take risks in situations where you do not have enough information or knowledge. The owl that comes out at night represents someone who chooses to act in darkness or without precaution. Swinging in the moon’s darkness might lead to injuries because you can’t see the danger. In other words, one needs to be careful and well informed before taking action. The equivalent English proverb would be ‘Fools rush in where angels fear to tread’.