Effects of hunting and non-hunting mortality on seasonal bobwhite densities in Tennessee

This thesis delineates some of the effects of hunting and non-hunting mortality on bobwhite populations on 8 study areas in middle and eastern Tennessee. Bobwhite population levels were measured via direct counts prior to (fall) and following (spring) annual hunting seasons from 1987 through 1991. The objectives of the study were to measure selected seasonal population levels and annual changes, determine effects of hunting and non-hunting mortality on measured population parameters, and assess hunting effort exerted on an intensively hunted area. The principal hypothesis investigated was that hunting and non-hunting mortality affected seasonal population levels and annual changes differently. Fall densities on the 8 study areas ranged from 16 to 126 bobwhites per 100 ha, and spring densities varied from 0 to 46 per 100 ha. Spring densities were positively related (P < 0.05) to fall densities. Fall densities directly affected (P < 0.05) succeeding fall densities. Fall densities significantly (P < 0.05) influenced losses over winter, but had no effect on both hunting and non-hunting mortality when these two types of mortality were partitioned and compared separately. Declines in fall populations over winter varied from 0.0% to 100% on exploited areas. Populations unexploited by hunting had over-winter reductions ranging from 37.3% to 93.2%; 1 nonhunted population increased over winter. Hunting mortality ranged from 3.4% to 93.9% of fall densities. Non-hunting mortality for exploited populations reduced fall densities 3.3% to 96.6%, while unexploited populations recorded non-hunting losses of 37.5% to 93.2%. Hunting and non-hunting mortality rates for exploited populations were not correlated. From 1988-89 through 1990-91, hunting mortality operated as a compensatory form of reduction, while in 1987-88, hunting was at least partially additive on one study area. Summer gains were inversely related to spring densities (P < 0.05). Spring populations increased 5.3% to 441.5% over summer. Hunted populations increased over summer throughout the study. Non-hunted populations increased some years on some areas and decreased on others. No statistical relationship existed between hunting mortality and over-winter losses, summer gains, and fall-fall changes. Proportions removed by causes unrelated to hunting were highly correlated with spring densities, over-winter losses, and summer gains, but not correlated with fall-fall changes. On the intensively hunted Jones study area, total harvest, hunter success, and hunting pressure varied appreciably from year to year, but the average per trip afield for these variables differed little among years.