Aspects of hunting of Northern bobwhite populations: temporal and spatial analysis

Northern bobwhites (Colinus virginianus) have been studied intensively now for more than a century. Despite the attention, widespread declines have occurred across their geographic ranges. These declines raise concerns regarding the long-term sustainability of populations exposed to hunting. However, population trends of northern bobwhites in South Texas seem to lack the long-term declines occurring across much of the state and elsewhere. Research has attributed this to favorable range management practices, large property sizes, and economic incentives derived from hunting lease fees in the region. The recommended harvest rate for South Texas is 20% of the fall abundance, including factoring for crippled individuals. This harvest rate is based on simulations of empirical data but still requires thorough evaluations in the field. We assessed the 20% recommendation during the 2018–2019, 2019–2020, and 2020–2021 hunting seasons on East Foundation properties in Jim Hogg County, Texas, using designated hunted (15,030 acres) and non-hunted sites (10,813 acres). We estimated multi-temporal bobwhite densities (e.g., 4 per hunting season × 3 seasons) using line-transect distance sampling from a helicopter platform and recorded bobwhite hunting details using Garmin GPS units (i.e., trucks and pointing dogs) and detailed hunting logs. Our specific objectives were to (1) evaluate the harvest rate recommendation for northern bobwhite populations in South Texas by comparing temporal trends between hunted and non-hunted sites (Chapter 2), (2) analyze the temporal and spatial dynamics of quail hunts in South Texas (Chapter 3), and (3) evaluate the spatial effects of harvest-related hunting pressure on local distributions of northern bobwhites (Chapter 4). According to our bobwhite density estimates, spring densities on both sites (e.g., hunted vs. non-hunted) were similar through the first two years but diverged in 2020–2021, with bobwhite densities 129% higher on the non-hunted site (Chapter 2). Hunting parties effectively covered 23.8 ± 0.3 hectares per hour, with hunts lasting 3.5 ± 0.1 hours in the morning and 1.7 ± 0.1 hours in the evening (Chapter 3). We also found that hunting pressure associated with a 20% harvest (i.e., low hunting pressure; 5.3–8.3-gun hours/100 ha) has a minimal influence on the change in bobwhite density at 16 ha resolution, with the year (i.e., starting or peak density per year) as the primarily influence (Chapter 4). Our results will assist managers in making decisions regarding sustainable harvest practices and aid with the strategical distributions of hunting pressure across properties and hunting seasons