There was once a nightingale, in a cage by a window, who was in the habit of singing only at night. An owl was puzzled by this and went to ask the nightingale what the reason was.
'When I was captured," explained the nightingale, 'it was day and I was singing. In this way I learnt to be more prudent to sing only at night.'
'Are you afraid, you might be captured a second time?' asked the baffled owl. 'It would have been better if you had been more careful the first time when your freedom was at risk. Now it doesn't really matter anymore!'