Predation by long-tailed weasels Mustela frenata during a Richardson's ground squirrel Urocitellus richardsonii population outbreak in southwestern Saskatchewan

摘要

Long-tailed weasels (Mustela frenata) are known to feed on mice and voles. However, in the Canadian Prairies, where Richardson's ground squirrels (Urocitellus richardsonii) are abundant (particularly during drought periods), long-tailed weasel predation on these medium-size rodents is poorly documented. In this study, predation by long-tailed weasels on Richardson's ground squirrels was documented from April 2008 to September 2008 in southwestern Saskatchewan during a drought period. I found that Richardson's ground squirrel remains were the dominant food item in percentage of occurrence, volume, and biomass from April to July. In August-September, however, deer mice (Peromyscus maniculatus) and insects became more important. During years of Richardson's ground squirrel abundance, weasels may temporarily switch predation onto these rodents.