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Article Abstract – Kotler et al. (1988)

Title:

The effects of morphology and body size on rates of owl predation on desert rodents

Authors and affiliations:

Burt P. Kotler, Blaustein Institute for Desert Research, Ben-Gnrion University, Sede Boqer, Israel
Joel. S. Brown, Department of Biological Sciences,University of Chicago, Chicago, IL
Rosemary J. Smith, Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ
William O. Wirtz lI, Department of Biology, Pomona College, Claremont, CA

Citation:

Oikos 53: 145-152 (1988)

Abstract:

Predation has been implicated in promoting microhabitat partitioning among desert rodents, but little direct evidence exists on how microhabitat or rodent morphology affect predation rates. We measured rates of predation by barn owls (Tyto alba) on heteromyid rodents which differ in body size (Perognathus amplus versus P. baileyi) and morphology (P. baileyi versus Dipodomys merriami). The experiments were conducted in a large, semi-natural enclosure. Owls captured the larger species at a significantly higher rate than the smaller species. We were unable to detect a consistent effect of rodent morphology on rates of predation. Also, rates of predation were higher for full moon levels of illumination than for starlight levels. In a separate experiment, we demonstrated that rates of predation are higher on rodents foraging in the open than on rodents foraging with cover. The results support the hypothesis that desert rodents represent a community where predation and competition interact directly to determine rodent foraging behavior and species interactions.

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