Sex‐related differences in the diet of the mink Mustela vison

Abstract
The diets of free‐ranging male and female mink were sampled by analysing faeces collected from radio‐tagged individuals. Significant sex differences were apparent in the predation upon three of the five principal prey groups. The larger males preyed much more heavily upon lagomorphs, the largest prey taken, while females preyed more upon fish and crustaceans than did males. These differences were consistent in each season except the autumn (September to November), when males preyed more heavily upon fish and crustacea than did females. Due to their large size, adult lagomorphs are felt to be relatively unavailable to female mink. Male mink are apparently large enough to specialize on lagomorphs, and male mink niche breadth was consistently lower than that of females. Dietary overlap approximated to 40% in all seasons except summer (68%), when female predation upon lagomorphs reached a peak. This reduction in intraspecific feeding competition was felt to be a valuable side‐effect of body‐size dimorphism.