Effects of leaf size on forage selection by collared pikas, ochotona collaris

Abstract

We examined the influence of leaf size on forage selection by collared pikas (Ochotona collaris) living in alpine meadows in the Yukon Territory, Canada, by comparing the winter diets of individually recognized pikas to the available vegetation within their territories and by conducting cafeteria-style preference experiments. Pikas consistently preferred forage with larger leaves in the cafeteria trials. They also collected larger leaves from deciduous shrubs and graminoid species compared to other plant types such as lichens and evergreen shrubs for their winter diets. Pikas assessed differences in leaf size when selecting their winter diets and this appears to be an energetically efficient foraging strategy for surviving seasonal food scarcity. © 2008 Regents of the University of Colorado.