The Cage-Bird and the Bat
A Singing-bird was confined in a cage which hung outside a
window, and had a way of singing at night when all other birds were
asleep. One night a Bat came and clung to the bars of the cage, and
asked the Bird why she was silent by day and sang only at night. "I
have a very good reason for doing so," said the Bird: "it was once
when I was singing in the daytime that a fowler was attracted by my
voice, and set his nets for me and caught me. Since then I have
never sung except by night." But the Bat replied, "It is no use
your doing that now when you are a prisoner: if only you had done
so before you were caught, you might still have been free."
— Precautions are useless after the event.