SEARCHING FOR CRYPTIC PREY - A DYNAMIC-MODEL

We present a dynamic model to examine sequential foraging decisions of predators searching for cryptic prey. We identify key elements of information processing and ecological factors determining the costs and benefits of two foraging alternatives. On the one hand, specializing on a single prey type while ignoring other types increases the distance a forager must move; this involves increased energy and time expenditures. On the other hand, switching between searching for several prey types has the obvious cost of an initial reduction in the probability of detecting prey immediately after switching. Switching also has the less apparent cost of a forager's reduced ability to assess the probability of prey presence. We show that if the cost of switching is sufficiently high, and a forager estimates that one prey type is more common than others, then the forager should search for this prey only, unless conditions change.