Diet of the Prairie Rattlesnake, Crotalus viridis viridis, in southeastern Alberta

Abstract

The diet of the Prairie Rattlesnake, Crotalus viridis viridis, in a multiple land use area in southeastern Alberta was investigated by examining the gut contents of 20 road-killed individuals and the composition of eight scats recovered from sequestered individuals. All individuals yielding dietary data were adults. No data on the composition of the local small mammal community are available. The number of prey items per snake varied (gut contents: 0-4 items; scat samples: 1-3 items). Frequency of occurrence (individual prey items) was: Sagebrush Vole (Lagurus curtatus) - 53% gut contents, 68% scats; Meadow Vole (Microtus pennsylvanicus) - 38% gut contents, 8% scats; Olive-Backed Pocket Mouse (Perognathus maniculatus) - 8% scats; Western Jumping Mouse (Zapus princeps) - 8% scats; Richardson's Ground Squirrel (Spermophilus richardsonii) - 8% scats; unidentified passerines - 9% gut contents. Although individual rattlesnakes sometimes took more than one prey taxon (gut contents: 1-3 taxa; scat samples: 1-2 taxa), multiple prey items in a single gut were almost always of the same species, suggesting that individual rattlesnakes tend to exploit patches where colonial burrowing prey species are abundant.