Prey Availability and the Food of Predators

Two models to predict the food of predators are proposed. They assume that prey size and prey abundance are the only availability factors of importance to predators. One model assumes that the predator consumes prey as they are encountered, and the other that predators feed to maximize their energy intake. Previous work, principally from aquatic situations, is examined to test the models. It is concluded that many invertebrates and larval vertebrates eat prey as they are encountered while adult vertebrates feed as energy maximizers. The limitations of the models are discussed and their relation to models of optimal diet examined.