Effects of Body Size and Sex of Drymarchon couperi (Eastern Indigo Snake) on Habitat Use, Movements, and Home Range Size in Georgia

The federally threatened eastern indigo snake (Drymarchon couperi), native to the southeastern Coastal Plain of the United States, has experienced population declines caused primarily by habitat loss, degradation, and fragmentation. To examine spatial and habitat use requirements of the species, we radiotracked 32 eastern indigo snakes from 2002 to 2004 on Fort Stewart Military Installation and adjacent private lands in Georgia. We estimated annual and seasonal home ranges and evaluated a priori hypotheses examining morphometric and ecological factors (sex, body size, location) associated with intraspecific differences in home range size. We analyzed habitat use hierarchically by examining use across the study area and within home ranges. Annual home range size varied from 33 ha to 1,528 ha (average minimum convex polygon: (x) over bar (2003)=378 ha; (x) over bar (2004)=340 ha). Individual home range size was most influenced by sex (males with larger home ranges) followed by body size. Compositional analysis of habitat use suggested positive selection for wetland, evergreen forest, and pine-hardwood (mixed) forest, with an avoidance of roads and deciduous forests. Seasonally, indigo snakes used the highest diversity of habitats as they moved from xeric uplands (sandhills) in winter and early spring to wetlands and uplands other than sandhills in summer; however, snakes continued to use sandhill habitats (35-58% of locations seasonally) with gopher tortoise (Gopherus polyphemus) burrows throughout the warmest months. In Georgia, management and conservation of the eastern indigo snake should include conservation of large tracts of undeveloped land, containing a matrix of xeric uplands with suitable underground shelters and adjacent wetland habitats. (c) 2013 The Wildlife Society.