According to Hsu Pao-hsiung, a research assistant at the department, farmers along all the Taitung-Hualien rift valley's three northsouth flowing rivers, the Hualien River, Hsiukuluan River and Peinan River, occasion ally see flocks of wild geese and ducks, but they only invade rice paddies in the area concentrated on the middle reaches of the Hsiukuluan River, in the Yuli area.
花蓮農改場植保股助理研究員徐保雄表示，花東縱谷由北而南的三條溪流，花蓮溪、秀姑巒溪、卑南溪沿岸，農民偶爾都會見到雁鴨群，但侵入農田、造成損害主要集中在秀姑巒溪中游玉里一段。