On the night the evacuation order was given from the camp at the Fuji-gawa River, tens of thousands of water birds that had been gathering on Fuji-numa Marsh flew up all at one time, the noise frightening the Taira soldiers and making them run in panic, assuming that the enemy was storming them.
富士川の陣から撤収の命が出た夜、富士沼に集まっていた数万羽の水鳥がいっせいに飛び立ち、その羽音を敵の夜襲と勘違いした平氏の軍勢はあわてふためき総崩れとなって敗走する。