Effects of Snow on Foraging Ecology and Nutrition of Bighorn Sheep

Abstract

We studied foraging behavior, diet quality, and activity budgets of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) under different snow cover conditions on a Ponderosa pine (Pinus ponderosa)-shrub-bunchgrass range in the montane zone of Colorado. Snow 2-12 cm deep persisted for less than a day to several weeks and caused bighorn to nose or paw to reach forage. Biting rates were reduced during periods of snow cover as were dry matter intake rates, despite an increase in bite size. Percentage of green material in the diet declined as snow depth increased, as did percent protein and dry matter digestibility of diets