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(Morristown National Historical Park)

Technical Report NPS/NER/NRTR—2007/087

Pauline A. Salmon and H. Brian Underwood

USGS-Patuxent Wildlife Research Center
State University of New York
College of Environmental Science and Forestry
Syracuse, NY

May 2007

U.S. Department of the Interior
National Park Service
Northeast Region
Boston, Massachusetts


Executive Summary

Contraceptives that work through the immune system are increasingly viewed as an acceptable alternative to lethal methods of managing overabundant white-tailed deer (Odocoileus virginianus). However, a recent workshop demonstrated that fertility control is still in the experimental stages. No guidelines or tools exist to aid managers in making decisions as to when, or even if, to use fertility control in deer management plans. In order to examine aspects of deer biology and site-specific factors which impact the feasibility of fertility control programs, we conducted fieldwork at Morristown National Historical Park (MNHP), Morristown, NJ. We characterized deer density and herd composition on a seasonal basis from 1996-98 using distance sampling methods. In addition, we compared deer encounter rates between land cover-types and between moving vehicles and established bait sites. Finally, we marked sixteen deer to assess heterogeneity in individual encounter rates. We found that feasibility, using current technology, is affected by population density, herd composition, cover-type utilization, flight response and access to deer. The integration of these factors determines the encounter rate with deer and thereby the effort required to achieve population objectives. A simulation model of a fertility control program was created in order to describe the feasibility of using fertility control in a variety of circumstances, and to determine the resources needed in each scenario. The model, constructed using STELLA® Research and driven by our field data, was also used to explore the implications of using fertility control as a population reduction tool rather than a population maintenance tool.


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