What Roadkills Did We Miss in a Driving Survey? A Comparison of Driving and Walking Surveys in Baldwin County, Georgia

Abstract

Accurate estimates of vertebrate road mortalities are necessary prior to the consideration of mitigation measures by resource managers. Due to ease of implementation, driving surveys are more common than walking surveys. From February 2018 to February 2019, two survey methods, driving and walking, were used to monitor a 1.16 km section of Highway 212 in Baldwin County, Georgia. Roadkills were identified and monitored for persistence from sunrise to noon two days a week. Twenty-nine roadkills were recorded over the survey period: 48.3% mammals (14/29), 27.6% herpetofauna (8/29), and 24.1% birds (7/29). Forty-eight percent (14/29) of roadkills were missed by the vehicle survey: 75.0% of herpetofauna, 43.9% of birds, and 35.7% of mammals. Of the roadkills missed, 72.7% (8/14) were located in the roadway compared to the verge. Carcasses smaller than eastern gray squirrel size were more likely missed in the driving survey than those equal to or larger than squirrels (c2=4.36; p=0.04). This study demonstrates that driving surveys miss a significant portion of roadkills and conducting walking surveys separately or in combination with driving surveys is necessary for an accurate estimate of vertebrate road mortality