《资治通鉴·隋纪·隋纪四》
乌程有棵很高的树超过百尺，树周没有可以攀附的枝条，树上有鹤巢，有人要捉鹤，但爬不上树，就砍伐树根。鹤怕它的后代被杀，就自己把羽毛拔下来扔在地上。当时有人称之为吉祥的征兆，说： 天子制羽仪，鸟兽自动献羽毛。 
乌程有高树，逾百尺，旁无附枝，上有鹤巢，民欲取之，不可上，乃伐其根；鹤恐杀其子，自拔氅毛投于地，时人或称以为瑞，曰： 天子造羽仪，鸟兽自献羽毛。 
There was a very tall tree in Wu Cheng, over 100 feet tall, and there were no branches on the tree that could be attached to, and there was a crane's nest in the tree. Someone wanted to catch the crane, but could not climb the tree, so he cut down the roots of the tree. The crane, fearing that its offspring would be killed, plucked out its own feathers and threw them to the ground. At that time some people called it an auspicious omen, saying: "The emperor made feather clothes, and the birds and beasts presented their feathers automatically."