A 49-year-old man surnamed Liu was hiking alone from Qingtian Gang toward Fengzui Zui yesterday evening when he encountered a large herd of bison blocking his path and trapping him. He quickly called 119 for help. The Taipei City Fire Department braved thick fog and used the sound of a whistle to locate him by ear, eventually finding Mr. Liu, but the herd of bison had already disappeared.