Document: JOE-3-56-36

Ecology of fear: Foraging games between owls and gerbils .

BROWN, J.S.* ¹, B.P.KOTLER ² and A.BOUSKILA ²

University of Illinois at Chicago, Chicago, IL, 60607, U.S.A. ¹
Ben-Gurion University, Sede Boqer Campus, 84990, Israel ²

Abstract:
We modeled a foraging game between a forager and its predator when the forager's resource is pulsed. For gerbils inhabiting sand dunes in Israel, for example, seed abundance is highest at dusk and declines throughout the night. The early gerbil gets the seeds but the early gerbil attracts owls. At the ESS of the model, rodent and owl activity should peak at dusk and decline throughout the night. The model predicts three phases of activity. In the first, all prey and all predators forage actively. During the second, a constant fraction of prey remain active while the activity of owls declines steadily. During this phase the capture rate of predators remains constant and the prey experience a constant ratio of risk to net energy return. During the third phase, resources become so depleted that all prey and predators remain inactive. The behavioral game stabilizes the predator-prey interaction for two reasons: 1) The prey have a behavioral refuge, and 2) the predators, via the fear responses of the prey, negatively effect their ability to capture prey.

Keywords: predator-prey interaction, foraging game, predation risk, ESS, vigilance, barn owl, gerbil

This abstract is being presented at: 4:45 PM in session:
Oral Session #17: Mammalian Herbivory.