Knowledge Bank

Although many factors are known to contribute to the population declines of the northern bobwhite (Colinus virginianus), in the Midwestern U.S. the greatest threat to northern bobwhite populations is thought to be dramatic changes in land use. Over the past century, the shift away from a diverse landscape characterized by low-impact agriculture to a landscape dominated by hardwood forests, invasive agricultural practices, and increasing development is believed to have drastically reduced habitat suitability for the northern bobwhite. No study thus far had addressed these issues in southwest Ohio. Nine routes (4 low abundance, 5 high abundance) were chosen based on call count data collected from 1984-2003. Routes with an average of 2 or fewer bobwhites detected per year were classified as low abundance, and routes with an average of 5 or more bobwhites detected along them were considered high abundance. After covermapping all 9 of these routes, I digitized existing habitat surrounding call count stops in GIS and outputted the percentages of different habitat types. Call count data collected by the Ohio Division of Wildlife from 2003-2005 was compared with these habitat percentages, ttests were run on individual habitat variables, and information theoretic methods (AIC) were used to evaluate the fit of 19 constructed logistic regression models, including one null model. Only the model containing developed habitat scored higher than the null model but not high enough to indicate any significant relationship between bobwhite occurrence and the habitat variable. The results indicate that potential bias might exist in the viability of call count routes as a true measure of quail abundance. Bias could also be related to small sample size.