Black Bear Harvest and Nuisance Behavior in Response to Gypsy Moth Infestation

Yearly food supplies influence black bear (Ursus americanus) harvest and nuisance behavior. During 1987-1990, gypsy moth (Lymantria dispar) infestation in northwestern Virginia, especially in Shenandoah National Park (SNP), resulted in widespread defoliation, acorn failure, and subsequent alterations in bear behavior. We believed canopy opening and especially acorn failure would lead to increased hunter harvest and nuisance behavior in defoliated regions of Virginia. In the defoliated region of Virginia, 138 ± 12 bears/yr and 220 ± 12 bears/yr were harvested before (1980-1986) and during infestation, respectively (P = 0.03). In addition, proportion of females harvested in this region increased from 34% to 40% (P = 0.09). These increases may have resulted from increased bear movements in fall and, hence, greater bear susceptibility to hunting during infestation. Significant differences in harvest or harvest sex ratios before and during infestation could not be demonstrated in regions of Virginia not experiencing defoliation. Number of nuisance bears captured near SNP during 1987-1990 was twice that during 1981-1986, but the increase may have been unrelated to gypsy moth infestation; fall nuisance activity showed little increase despite acorn failure. Nuisance behavior within SNP was not affected by canopy loss or acorn failure. Defoliation enhanced soft mast production and may have allowed bears to avoid turning to higher levels of nuisance activity that might be expected during more conventional hard mast failures.

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