AUTHORS: Nicholas F Sekits, Department of Biology, Loyola University Chicago; Sara Ruane, Field Museum of Natural History; Joseph R. Milanovich, Department of Biology, Loyola University Chicago
ABSTRACT: Midwestern snake populations are in decline therefore an understanding of their ecology is paramount. This understanding is often lacking since snakes are cryptic and difficult to capture. Many sampling techniques have arisen to combat this such as drift fence-trap configurations and coverboards with varying levels of investment for researchers. Our study examined whether time of sampling, type of coverboard (rubber mats or carpet squares), and temperature influenced the number of captures or size of individuals at capture for two common species of snakes found in northern Indiana, Common Gartersnake (Thamnophis sirtalis) and Dekay’s Brownsnakes (Storeria dekayi). We deployed 30 coverboards (20 carpet and 10 rubber mats) at 20 sites across a 12-county area in northern Indiana. Coverboards were checked every 14 to 28 days and all snakes captured were identified and measured. We used general linear models to examine what factors predicted captures and size at capture. Our results show that month significantly predicted captures of T. sirtalis, but not S. dekayi, where T. sirtalis were captured at higher rates in July and August compared to April, May and June. Size of snakes at capture was predicted by month for both T. sirtalis and S. dekayi (and temperature for T. sirtalis) with captured snakes being significantly smaller in August compared to other months. We found no significant difference in captures between coverboard types. These results suggest both species show no preference between board types, T. sirtalis use cover at higher rates in July and August, and utilization of cover by larger snakes of both species declines in August.
