Simon Liao, president of the Taiwan International Birding Association, explains that besides having different winter and summer plumages, many waterbird species are very similar in size and shape, and may only differ in the color of their feet. If they are standing on a mudflat, this makes recognition all the more difficult. This is one reason why advanced birders enjoy the challenge of watching waterbirds.
國際台灣觀鳥協會理事長廖世卿解釋，水鳥除了冬、夏羽之分外，很多鳥種外型、大小相似，差別只在腳的顏色，若是又踩在泥灘中，更增分辨時的困難，這也是高段的賞鳥人喜歡挑戰水鳥的原因。