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Sidewinder Inventory at Saguaro National Park 2022 - Open Format Dataset

Published by National Park Service | Department of the Interior | Metadata Last Checked: January 25, 2026 | Last Modified: 2024-04-30T00:00:00Z
Saguaro National Park, Tucson Mountain District (TMD) includes a portion of the Tucson Mountains and adjacent lower bajada landscapes along the western boundary in Avra Valley. Plans to route Interstate 11 within 400 m of the western boundary have led to concerns over projected negative impacts on wildlife. Among the species of concern is the Sidewinder (Crotalus cerastes), primarily because the population residing in TMD represents the easternmost distribution of this iconic species. To better inform management, we used distance sampling along transects and washes and road cruising surveys to examine density and distribution of Sidewinders in TMD. From May-September, 2022, encompassing both the dry pre-monsoon season and the wet monsoon season, we conducted 519 distance sampling surveys totaling 814.61 km and 69 road cruising surveys totaling 1,997.47 km in upland and wash environments. Our efforts produced 421 total snake observations, which included nine Sidewinder observations. The small number of Sidewinders observations proved to be insufficient for model convergence. Although we were unable to obtain density estimates of Sidewinders, data from both distance sampling and road cruising surveys provided valuable information on distribution of the species. As expected, we observed Sidewinders in the westernmost portion of TMD in sandy environments dominated by yellow palo verde and creosote bush. We recommend that TMD staff conduct repeated road cruising surveys over time to make inferences about population trends that can be compared before and after construction of I-11.

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