Female Reproductive Ecology of Western Rattlesnakes (Crotalus oreganus) in Southern British Columbia

Eye, Dana M.

Environmental Science Program

Thompson Rivers University

Kamloops, British Columbia, Canada

danaeye03@gmail.com

Skurikhina, Anna

Department of Natural Resource Science

Thompson Rivers University

Kamloops, British Columbia, Canada

Bishop, Christine

Environment and Climate Change Canada

Delta, British Columbia, Canada

Larsen, Karl W.

Department of Natural Resource Sciences

Thompson Rivers University

Kamloops, British Columbia, Canada

klarsen@tru.ca

Female reproductive success, habitat selection and behaviour are all important elements in rattlesnake ecology. In Canada, a large portion of research on the Western Rattlesnake (Crotalus oreganus) has focused heavily on male behaviour (including migration), leaving a large knowledge gap and biasing the development of effective recovery plans. Our study in Osoyoos, BC, is focusing on site selection and movement behaviour by female rattlesnakes during parturition. We are using radio telemetry to track gravid female rattlesnakes (n=15 to date) to their ‘rookery sites’, identified by the cessation of long-distance movements and the adoption of sedentary behaviour. These sites are being compared to random habitat plots using a matched case-control study design. Vegetation cover, temperature data, and additional features are being assessed at three different spatial scales (1 m, 3 m, & 10 m radius plots). To date, we have identified 14 rookery sites and 7 communal rookery sites. The average distance traveled by gravid females from their hibernacula to their rookery sites is 84.7 m (range 7.4 m to 233.2 m, n= 15). Additionally, 12/15 females moved down slope, following parturition, in the opposite direction of their hibernacula. This spring, gravid female rattlesnakes will be radio-tracked at three different sites in BC, in addition to provisioning experiments, to investigate the potential drivers of post-partum rattlesnake movement. Information from this ongoing study will shed insight into a critical phase of the life history of female rattlesnakes in this region.


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