Alien versus Alien: The American mink, Neovison vison, as an indicator of invasive crayfish presence in the environment

•The mink’s dietary composition showed great similarities across study sites.•The basic diet consisted of rodents, amphibians, and fish.•The presence of crayfish in the samples was dependent mostly on insects.•The percentage of crayfish in scats was correlated with crayfish density.•Crayfish density calculations based on mink’s diets may differ during droughts.