HUNTER DISTRIBUTION AND HARVEST OF FEMALE WHITE-TAILED DEER IN PENNSYLVANIA

Open Access
Author:
Keenan, Matthew Thomas
Graduate Program:
Wildlife and Fisheries Science
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
October 22, 2010
Committee Members:
  • Duane R Diefenbach, Thesis Advisor
Keywords:
  • harvest
  • hunter density
  • hunter distribution
  • hunting efficiency
  • hunting mortality
  • Odocoileus virginianus
  • Pennsylvania
  • survival
  • white-tailed deer
  • antlerless
Abstract:
ABSTRACT In 2001 and 2003, the Pennsylvania Game Commission increased opportunities for hunters to harvest antlerless white-tailed deer (Odocoileus virginianus) as part of an effort to change the densities and age-sex structure of deer populations in most wildlife management units. However, areas that experience low levels of hunting effort and deer harvest may serve as de facto refugia where such regulation changes could have little influence on deer densities. Knowledge of spatial variation in deer harvest and hunter distribution may help managers direct hunting effort to more effectively regulate deer densities. I captured, collared, and monitored 231 antlerless white-tailed deer from 2005 to 2006 surrounding the Sproul State Forest in north-central Pennsylvania and the Tuscarora State Forest in south-central Pennsylvania. I monitored deer on a weekly basis to estimate annual survival and harvest rates and to model spatial distribution of hunting mortality. I conducted aerial surveys of hunters during the 12-day rifle hunting seasons in 2005 and 2006 on these same areas to estimate hunter density and to model hunter distribution. I compared the distributions of hunters and hunting mortality to identify spatial variation in hunting efficiency. Lastly, I used these models to predict the effect of an expanded road network on hunting mortality and refugia. Point estimates indicated that on the Sproul study area, annual survival was greater on public land (89.9%, 95% CI = 84.0-96.1%) than private land (75.5%, 95% CI = 66.7-85.6%), but was the opposite on the Tuscarora study area (60.9%, 95% CI = 49.4-75.2% on public land and 75.5%, 95% CI = 66.7-85.6% on private land). Point estimates indicated harvest rates on the Sproul study area were almost four times greater on private land (16.7%, 95% CI = 8.4-33.2%) than on public land (4.4%, 95% CI = 1.8-10.8%). On the Tuscarora study area, harvest rate did not vary between public and private land, but point estimates indicate subadults were harvested at almost twice the rate (30.3%, 95% CI = 19.0-48.1%) as adults (16.4%, 95% CI = 9.4-28.6%). The high survival and low harvest rates on public lands in the Sproul study area suggest that hunting may have a limited effect on deer population dynamics. Hunter density on both study areas was greatest early in the hunting season. On the Sproul study area, a maximum hunter density of 1.1 hunters/km2 was observed on both public and private land during opening day of the rifle season. Hunter densities on public portions of Tuscarora study area ranged from 0.9-1.2 hunters/km2 over the first two days of the rifle season. Hunter density on Tuscarora’s private lands was lower, with a maximum hunter density of 0.5 hunters/km2 observed on opening morning. On both the Sproul and Tuscarora study areas, hunter use generally declined with increasing distance from the nearest public road and with increasing slope of the landscape. On the Sproul study area, 73% of hunters on public land were located <600 m from a road, compared to 60% of the area being within that distance and 70% of hunters used slopes <8°, which represented 57% of the area. Hunters on private lands on the Sproul study area were uniformly distributed by distance from road, but 79% of hunters were on slopes <8°, which represented 73% of the area. On the Tuscarora study area, 79% of all public land hunters remained <600 m from a road, compared to 69% of the area being within that distance, and hunters tended to avoid steeper slopes, although the effect was not as great as on the Sproul study area. Hunters on private land in the Tuscarora study area avoided locations both near and far from roads and slope had little relation to the distribution of hunters. I found no spatial variation in deer hunting mortality rate on the Tuscarora study area. On the Sproul study area, hunting mortality was highest close to roads, likely because hunter use was concentrated in those areas. On public land, 74% of all hunting mortality occurred <500 m from a road, although only 53% of the area was within that distance. On private land, 87% of all hunting mortality occurred <500 m from a road, compared to 74% of the area being within that distance category. Slope of the landscape, however, had little influence on deer hunting mortality. Hunting efficiency was not uniform across the landscape, indicating deer were more vulnerable to harvest in some areas, regardless of hunting pressure. Hunters were most efficient 500–1,000 m from a road and on moderate slopes between 10 and 20 degrees. Hunting efficiency also increased with increasing hunter use, except in areas of greatest use. The Sproul study area contained >4,000 ha of de facto refugia that experienced hunting mortality rates of <2%, and increased opportunities for hunters to harvest antlerless deer may have little effect on deer densities in these areas. Increasing hunter access to refugia may be an effective way to control local deer populations and expanding the public road network to include all gated and unimproved roads could potentially decrease the amount of refugia by 67%.