Size-selective predation of sa n moes by two species of ero

摘要: Two species of herons (Aves: Ardeidae), the great egret and snowy egret, fed preferentially on relatively large individual sailfin mollies (Pisces: Poeciliidae). The level selectivity by egrets decreased when plant cover was added to experimental conditions. We documented preference for in all combinations two prey sex ratios size distributions with 50% cover. Snowy chose females males were rare, but not they commmon. This may be caused larger overall gravid comparison same length and/or behavior are a minority relative males. Selective predation wading birds is likely contribute patterns variation among some populations female-skewed adults.