Risk sensitive foraging: an experimental study of a solitary marsupial.

Abstract

DETECTION and avoidance of predators are the principle strategies employed by prey to evade attack; by scanning their environment, prey individuals can reduce the likelihood of a predator approaching to within striking distance (Elgar 1989; Lima and Dill 1990). However, vigilance is often incompatible with foraging behaviours, and thus animals may be forced to trade-off the risk of predation against acquiring food. Consequently, the quality of a particular resource patch and its associated predation risk may influence the foraging decisions of animals (Werner et al. 1983; Newman and Caraco 1987; Heithaus and Dill 2002). Cover is an important feature of a foraging site because it can provide a hiding place to escape potential predators (Lazarus and Symonds 1992). Thus, animals may prefer foraging sites that are close to cover, or adjust their level of vigilance at different distances from cover in order to compensate for changes in the chance of early detection and escape (Elgar 1989; Lima and Dill 1990; Lima et al. 1985; Kramer and Bonenfant 1997).