Lin Wen-hung says that from looking at maps he judged that birds returning northwards from Kenting only had a few high spots to choose from as places to rest before setting off over the ocean. The only highish areas in Northern Taiwan are the Yangming Mountain range and Mt. Kuan-yin. The Yangming range runs east to west, but the migrating birds 'route takes them from south to north.
林文宏說，他由地圖研判，從墾丁北返的鳥，會選擇某幾個高點歇腳，再出海，北部較高的地區，只有陽明山系和觀音山。