Food habits of California voles, Microtus californicus, in artichokes, Cynara scolymus

Abstract

The California vole ( Microtus californicus) is the most serious vertebrate pest of artichokes ( Cynara scolymus) in California. A microhistological analysis of the stomach contents of 45 voles collected at intervals from November 1983 to July 1985 from seven different artichoke fields indicated that artichoke was a significant and the major component of their diet during all seasons. In the spring (April) collections, the amount of artichoke consumed was somewhat reduced and about equal to all other food items combined due to increased consumption of grasses (wild oat, Avena fatua, and common foxtail, Hordeum leporinum) and/or oxalis ( Oxalis pes-caprae) at that time of year. Other items consumed in relatively minor amounts by voles in artichoke fields were cheeseweed ( Malva parviflora), chickweed ( Stellaria media), mustard ( Brassica spp.), and insects. This study clearly illustrates that artichoke may comprise the bulk of the diet of California voles and in part explains the severity of the damage they often cause. The reasons for apparent seasonal dietary shifts are discussed.