HOCHMAN, Valeria; KOTLER, Burt; Ben Gurion University of the Negev; Ben Gurion University of the Negev: Measuring foraging behavior of Nubian Ibex under predation risk

For Nubian ibex (““Capra nubiana”“) cliffs provide refuge from predators, but may not provide foraging opportunities. Therefore it is expected that for ibex seeking food away on plateaus away from the cliff, as distance to refuge increases, so does predation risk and the predation cost of foraging. Therefore, the farther from the cliff edge an animal is, the higher its vigilance level is expected to be and the higher should be its quitting harvest rates when exploiting food patches. In order to assess the effects of various variables that may affect the foraging behavior of Nubian Ibex, giving-up densities (GUD) in artificial food patches and apprehension level were measured. Habitat preferences and patch selectivity as a measure of apprehension were considered. It was predicted that: the riskier the habitat, the higher the G.U.D and greater the selectivity of Nubian Ibex for a more abundant or easier to handle food resource. The GUD technique was applied using feeding trays as artificial resource patch following Kotler et al, 1994. It was found that GUDs for Nubian Ibex were higher farther from the cliff, indicating that distance to cliff edge affect risk of predation. Furthermore, GUD were affected by the distribution of food in the food patch. In addition, it was established that in risky habitats the selectivity of Ibex for a more abundant or easier-to-handle food resource was greater. Finally, although patch use behavior of ibex does not support the use of apprehension in these animals, ibex instead employ the more extreme behavior of vigilance to help manage risk