Knowledge of habitat use and resource selection behaviours are critical to understanding the population ecology of any animal species. In some species, genders and age classes exhibit different preferences for foraging, reproduction, and shelter. The Western Rattlesnake (Crotalus oreganus) is a good example of a species that shows variation in habitat use between genders, mainly due to different reproductive life histories. My research focussed on identifying and describing gestation sites referred to as rookery sites used by gravid female rattlesnakes for parturition. Radiotelemetry was used to monitor twelve gravid females from April to September 2017 in Osoyoos, British Columbia. I assessed vegetation cover and other habitat features at the rookery sites across three different spatial scales (1 m, 3 m, 10 m radius plots). To compare rookeries to random habitat plots, I used a matched case-control study design. Conditional logistic regressions revealed that at the 1 m scale, females selected sites with higher surface temperature, whereas at the 3 m scale, they selected for higher air temperature and the sufficient cover of rocks. At the largest scale, 10 m radius plot, average air temperature once again was selected for by gravid females. Overall, rookery sites had 80% rock cover and were found on south-facing slopes (on average 26% slope incline). Information on the location, habitat structure and use of rookeries provides important insight into understanding the ecology of Western Rattlesnakes and facilitating their conservation.
