Factors Related to Nest Survival and Over-winter Survival of a Northern Bobwhite (<i>Colinus virginianus</i>) Population in Southwest Florida

The northern bobwhite (Colinus virginianus) is a gallinaceous upland game bird dependent on early successional grassland habitat for reproduction and survival. Bobwhite populations have been declining range-wide for nearly a half century. The habitat of Babcock-Webb Wildlife Management Area (BWWMA) in southwest Florida is mostly virgin, early successional grassland and pine flatwoods. Although BWWMA is located in the far southern end of the bobwhite range, the area is a popular public land for bobwhite hunting. The BWWMA bobwhite population has declined evidenced by a dramatic decrease in harvest over the last 20 years. The two objectives of my research were to (1) describe nest habitat selection and daily nest survival of the bobwhite population on BWWMA, and (2) evaluate factors related to over-winter (1 October – 30 March) survival of the BWWMA bobwhite population. Specifically, I evaluated nest-site habitat selection and modeled daily nest survival as a function of biologically meaningful spatial, temporal, climatic, and habitat related covariates (Part II). I tested the hypothesis that bobwhites selected nesting habitat at the landscape level. There was no evidence that bobwhites selected specific habitats for nesting, but basin marsh and wet flatwoods cover types were used for nesting slightly more than they were available. The incubation period nest survival rate was 0.477 (SE = 0.027). Daily nest survival rates did not differ among years, the hunting zone in which the nest was located, or between genders of the incubating bird. Nest survival was positively related to the percent of basin marsh habitat within a 1000-m radius of the nest. Daily nest survival declined over the nesting period. I modeled the over-winter survival rates of bobwhites as a function of hunting pressure and other spatial, temporal, climatic and habitat covariates (Part III). The average over-winter survival rate was 0.402 (SE = 0.023). Year, time, and hunting zone were important factors influencing over-winter survival. Hunting pressure was the factor most related to over-winter survival. I evaluated management oriented questions related to over-winter survival of bobwhites on BWWMA. Food strip management and prescribed fire did not appear to be related to over-winter survival. Harvest rates were greater than others reported from studies in the Southeast and results suggested that, to some extent, harvest was additive to natural mortality. If the goal of management is to increase the BWWMA bobwhite population, reduction in harvest rate is one likely effective management strategy for achieving that goal.