Extrinsic and Intrinsic Factors Influencing the Detectability of Eastern Diamondback Rattlesnakes (C

Colbert, Joseph E.

jcolbert@jekyllisland.com

Jekyll Island Authority Conservation Department Jekyll Island State Park

Jekyll Island, Georgia, USA

Andrews, Kimberly M.

kma77@uga.edu

Odum School of Ecology

University of Georgia

Brunswick, Georgia, USA

The Eastern Diamondback Rattlesnake (Crotalus adamanteus) ranges throughout the lower southeast Atlantic Coastal Plain of North America. Throughout their range, habitat destruction and loss to human development, agriculture, fragmentation, and direct persecution have resulted in their range-wide population decline. As a result, in 2011 the species was petitioned for federal listing under the Endangered Species Act. In response, to provide much needed information related to their populations where they still exist, we began radio-tracking eastern diamondbacks on Jekyll Island State Park in 2011. They can be found in habitats ranging from upland sandhills to high marsh and barrier islands throughout the southern Atlantic coastal plain. In 2014, at Biology of the Pit Vipers II, we presented information related to their habitat use on Jekyll Island, a partially developed barrier island on the Georgia coast. Eastern diamondbacks specialize in using habitat structure with dense vegetation at the ground level and limited to no canopy. This provides them needed concealment from prey they consume and megafauna that threaten them, including humans. Being a cryptic predator that resides in densely vegetated habitats, these snakes are extremely covert, which greatly complicates the ability of even trained herpetologists to detect individuals. Detectability is one of the most important information needs that can help facilitate population estimates and has the potential to support population modeling in the future. This year we present information related to detectability in varying habitats that they are found in throughout Jekyll Island. We assessed the frequency of visual detection of 31 telemetered individuals, and cumulatively found the snakes to be visibly exposed 26.2% of the time throughout 3,796 snake relocations. Here, we present these results along with factors that influence their detection assessments, including habitat type, density of ground and canopy cover, season, sex, and other factors that influence their detectability.