HABITAT USE, HOME RANGE SIZE, AND MOVEMENT RATES IN TWO SYMPATRIC PITVIPERS (CROTALINAE) IN FAR WEST TEXAS

Abstract Niche partitioning, or differential resource use, is a possible explanation for the coexistence of multiple species that would otherwise be in competition. In this study, we examined two sympatric desert snakes, the eastern black-tailed rattlesnake ( Crotalus ornatus ) and western diamondback rattlesnake ( Crotalus atrox ) on Indio Mountain Research Station (IMRS) in Hudspeth County, Texas, for evidence of partitioning along the spatial dimension of the niche. We tracked the movements of the two species using radiotelemetry and analyzed macrohabitat and microhabitat data using a combination of multinomial logit models and chi-square tests. Evidence of niche partitioning along the spatial dimension of the niche exists between the two species, with C. ornatus showing a higher affinity for southwest facing, rocky slopes and C. atrox showing a relatively diverse use of all habitats with a slight preference for northeastern slopes. Our results largely compare to previous studies at both IMRS and throughout the range of each species.