Biological invasions are occurring at an increasing rate globally and are coupled with growing costs of control and mitigation. Effective and robust methods are therefore required to enable reliable prediction of impacts of new and emerging invasive species to better inform management decisions. A recent approach for investigating invader impact focuses on the functional response, the intake rate of a consumer as a function of food density. Evidence from short-term experiments suggest that problematic invaders often exhibit higher resource intake at a given food density than natives. Thus, short-term experiments to characterize the functional response may be a useful tool for predicting which invaders will have detrimental impacts in natural ecosystems over longer time scales.