USING BEHAVIORALLY-BASED SEASONS TO INVESTIGATE CANEBRAKE RATTLESNAKE (CROTALUS HORRIDUS) MOVEMENT PATTERNS AND HABITAT SELECTION

Abstract

Both abiotic factors and behavioral patterns may influence snake activity. However, other than reproductive activities, behavioral patterns have rarely been incorporated into studies of snake habitat selection. We investigated seasonal differences in canebrake rattlesnake (Crotalus horridus) movement patterns and habitat selection. We modeled habitat selection in two ways, with and without regard to behaviorally-based seasons, and compared the two models to determine which yielded the most informative results. Behaviorally-based seasons (foraging, breeding, and hibernation) were determined from field observations of study animals. Habitat selection was modeled as habitat use versus availability using a case control sampling design for males and nongravid females using logistic regression. Males had significantly larger home ranges, moved more often, and traveled greater distances between successive locations during the breeding season as compared to nongravid females. The male no-season habitat model lacked significance, and the nongravid female no-season model revealed a positive association with pine savannas. When behaviorally-based seasons were included in the models, both sexes showed distinct seasonal variation in habitat selection, with males and nongravid females using similar habitat for breeding and hibernation, but partitioning habitat during the foraging season. Our results indicate that behaviorally-based seasons provide important details about intraspecific canebrake rattlesnake habitat selection and movement patterns, and that future research should benefit from the inclusion of snake behavior in habitat studies.