Predation on artificial nests of Northern Bobwhites, Colinus virginianus, by mammalian mesopredators: Does the problem-individual paradigm fit?

Abstract

Using mark/recapture procedures, predation on artificial nests of Northern Bobwhites (Colinus virginianus) by mammalian mesopredators (Raccoons, Procyon lotor; Virginia Opossums, Didelphis virginiana; and Striped Skunks, Mephitis mephitis) was assessed in relation to the "problem-individual" paradigm. The paradigm, which is untested among mammalian mesopredators, predicts that most predation on a prey species is by a small number of individuals repeatedly involved. By examining number of captures and recaptures on artificial nests during non-nesting and nesting periods in 2000-2003, predation wimin and among species were gauged. Results varied by species, sampling period, and year; however, predation was by a small percentage of individuals and only within the population of Striped Skunks were individuals (2 of 49) captured on an artificial nest more than once. Raccoons, Virginia Opossums, and Striped Skunks were responsible for 10, 2, and 12% of the loss of all nests available to predators, respectively. Based on low occurrences of individuals repeatedly involved in predation on nests, the problem-individual paradigm was unsubstantiated. Although Raccoons, Virginia Opossums, and Striped Skunks (as individual predators) had only moderate impact on the population of Northern Bobwhites, they had a much greater impact collectively (preying upon 24% of all nests available). To maximize Northern Bobwhite success, the most productive management is probably best directed toward a vertebrate guild that includes mammalian, avian, and reptilian predators, and management strategies that use multiple techniques.