本研究以最佳食性理論(Optimal Diet Theory)的觀點，探討東方環頸(Charadrius alexandrinus)的食性選擇。於1997 年11 月至1998 年1 月，在實驗室人造環境中，供給各分成三種大小等級的三種螃蟹：清白招潮蟹(Uca lactea)、短趾和尚蟹(Mictyris brevidactylus)及長趾股窗蟹(Scopimeralongidactyla) ，一共九個螃蟹項目在相同的密度下，進行東方環頸 覓食螃蟹種類、大小的食性選擇實驗。實驗結果顯示，三種螃蟹其獲利率皆隨螃蟹大小等級的增加而下降；而比較同大小等級的三種螃蟹，獲利率依序是長趾股窗蟹、清白招潮蟹、短趾和尚蟹。東方環頸在覓食同大小等級的三種螃蟹中，偏好長趾股窗蟹；覓食長趾股窗蟹時無大小偏好，對清白招潮蟹與短趾和尚蟹則偏好等級小者(p<0.05)。東方環頸的食性選擇符合最佳食性理論所預測，偏好獲利率高的螃蟹。

The aim of this study is trying to explain the diet choice of Kentish Plover (Charadrius alexandrinus)with the idea of optimal diet theory. Investigating the role of prey species (Mictyris brevidactylus,Scopimera longidactyla, Uca lactea ) and size (each species divided into three classes) in affecting prey choice of captived Kentish Plover from November 1997 to January 1998.Results of the laboratory study showed that profitability decreases with increasing size of three species
of crabs. Scopimera longidactyla is the most profitable prey and Mictyris brevidactylus is the least of the same size classes. Scopimera longidactyla and small classes of Mictyris brevidactylus and Uca lactea
were preferred (p<0.05). The prey choice of Kentish Plover consists with the optimal diet theory..