Spatio‐temporal variation in male white‐tailed deer harvest rates in Pennsylvania: Implications for estimating abundance

Abstract

The performance of 2 popular methods that use age-at-harvest data to estimate abundance of white-tailed deer is contingent on assumptions about variation in estimates of subadult (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 subadult and 225 adult male white-tailed deer across 4 WMUs from 2002 to 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 subadult 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 only the firearms season best explained harvest rates for subadult 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. ß 2011 The Wildlife Society.

Land use and dispersal influence mortality in white‐tailed deer

“…Hansen () observed lower deer densities on public lands that did not have antler‐based selective harvest criteria in excess of state regulation in Missouri, and public land hunters expressed poor harvest success and dissatisfaction with their hunting experience. Similarly, although public land use explained less variability in the harvest of males than metrics of hunter effort in Pennsylvania (Norton et al ), public land hunters were more likely to hunt with the goal of harvesting a male regardless of age class, less likely to harvest an antlerless deer, and less likely to view themselves as land managers (Stedman et al ). Although there was a greater density of hunters on public land relative to private land in our study, which may directly affect yearling male survival rates, differences in attitudes and objectives between public and private land hunters may confound the risk of harvest mortality for yearling males when harvest regulations are similar between landownership types.…”

Effect of paved road density on abundance of white-tailed deer

“…deer in Pennsylvania are estimated to range from~0.3 to 0.6 depending on hunting effort and location (Norton et al 2012), which is about 4-5 times the mortality rate due to road kill. The relative rates of harvest and road mortality in eastern Ontario are likely similar, although we do not have estimates for this area.…”

Monitoring der Seitenhafenbrücke in Wien

“…Hunter harvest data and estimation of survival and harvest rates of radiocollared deer provided the input required to estimate deer abundance using the PASAK model (Norton 2010, Norton et al 2012). We aged deer aged to 3 age classes, juvenile (6–10 months old), subadult (18–20 months old), and adult (≥30 months old), by evaluating tooth wear and replacement (Severinghaus 1949).…”

“…We estimated the adult male harvest rate ( H AM ) from radio telemetry data using logistic regression (Norton et al 2012). Hunter selection or avoidance of radio‐ or Global Positioning System (GPS)‐collared deer is possible (Jacques et al 2011), but we have failed to detect differences in male and female harvest rates among deer fitted with radiocollars, less visible ear tag transmitters (Wallingford 2012), and reward ear tags that were only detectable after a deer was harvested (D. R. Diefenbach, unpublished data) in Pennsylvania.…”

“…In 2002, the PGC initiated antler point restriction regulations, requiring antlered deer harvests to have ≥1 antler with either ≥3 or ≥4 points, depending on the wildlife management unit (WMU), which protect approximately 50% of the subadult (1.5‐yr‐old) male population from harvest. Most 2.5‐year‐olds and older male deer are legal to harvest and are subject to higher harvest rates (Norton et al 2012). Consequently, the age structure of the harvest does not represent the age structure of the population because of different harvest rates by age class.…”