Pennsylvania Project: Evaluation of the PA Sex-Age-Kill Model for White-tailed Deer

Pennsylvania Project

Evaluation of the PA Sex-Age-Kill Model for White-tailed Deer

October 2008 - May 2010

Personnel

Participating Agencies

Pennsylvania Game Commission

Andrew Norton with captured white-tailed deer

Readily available harvest data is frequently incorporated in models used to estimate abundance of game species. However, appropriateness of parameter estimates and assumptions using these data is rarely evaluated. This project used data across 10 years from >1,500 VHF and GPS collared white-tailed deer to provide parameter estimates and evaluate methods used to estimate white-tailed deer abundance in Pennsylvania. In addition, this project investigated spatial, temporal, and demographic patterns in harvest rates.

Research Publications

Research Publications	Publication Date
Norton, A. S., D. R. Diefenbach, B. D. Wallingford, C. S. Rosenberry. 2012. Spatio-Temporal Variation in Male White-Tailed Deer Harvest Rates in Pennsylvania: Implications for Estimating Abundance. Journal of Wildlife Management 76:136-143. \| Abstract \| Download	January 2012	The performance of two popular methods that use age-at-harvest data to estimate abundance of white-tailed deer is contingent on assumptions about variation in estimates of yearling (1.5 yr old) and adult (≥ 2.5 yr old) male harvest rates. Auxiliary data, e.g., estimates of survival or harvest rates from radiocollared animals, can be used to relax some assumptions, but unless these population parameters exhibit limited temporal or spatial variation these auxiliary data may not improve accuracy. Unfortunately maintaining sufficient sample sizes of radiocollared deer for parameter estimation in every wildlife management unit (WMU) is not feasible for most state agencies. We monitored the fates of 397 yearling and 225 adult male white-tailed deer across 4 WMUs from 2002-2008 using radio telemetry. We investigated spatial and temporal variation in harvest rates and investigated covariates related to the patterns observed. We found that most variation in harvest rates was explained spatially and that adult harvest rates (0.36–0.69) were more variable among study areas than yearling harvest rates (0.26–0.42). We found that hunter effort during the archery and firearms season best explained variation in harvest rates of adult males among WMUs, whereas hunter effort during the firearms season best explained harvest rates for yearling males. From a population estimation perspective, it is advantageous that most variation was spatial and explained by a readily obtained covariate (hunter effort). However, harvest rates may vary if hunting regulations or hunter behavior change, requiring additional field studies to obtain accurate estimates of harvest rates.

Presentations

Presentations	Presentation Date
Norton, A., and D. Diefenbach, C. Rosenberry, B. Wallingford. Evaluation of the Pennsylvania Sex-Age-Kill (SAK) Model for White-tailed Deer. Presented at the Southeast Deer Study Group Meeting in Roanoke, Virginia on February 24, 2009.	February 2009

Theses and Dissertations

Theses and Dissertations	Publication Date
Norton, A. S. 2010. An evaluation of the Pennsylvania Sex-Age-kill model for white-tailed deer. Thesis, Pennsylvania State University, University Park, Pennsylvania, USA.	May 2010

Cooperative Fish and Wildlife Research Units Program: Pennsylvania Education, Research and Technical Assistance for Managing Our Natural Resources