Responses of Redshank, Tringa totanus, to the Absolute and Relative Densities of two Prey Species

In many situations, a predator may select between several prey species which occur together in the same place. Its response in these circumstances may be determined by either the relative or absolute frequency with which it encounters the alternative prey (Murdoch & Oaten 1975). This paper examines the response of a wading bird, the redshank, Tringa totanus (L.), to variations in the relative and absolute abundance of two species of estuarine-invertebrates, the amphipod crustacean Corophium volutator (Pallas) and the polychaete worm Nereis diversicolor 0. F. Muller, which occur together in many places where redshank feed.