Diet of California bighorn sheep, Ovis canadensis californiana, in British Columbia: assessing optimal foraging habitat

Abstract

Fourteen grasses and sedges, 47 forbs and bryophytes, and 18 browse species averaged 66.6, 19.0 and 14.6% of the diet, respectively. Each forage group was selected by the sheep in proportions similar to average frequency on the site: bluebunch wheatgrass Agropyron spicatum comprised the most common diet component (20.5%), followed by prairie junegrass Koeleria cristata (13.9%), needle-and-thread Stipa comata (10.6%), rough fescue Festuca scabrella (8.0%), cheatgrass Bromus tectorum (4.6%) and arrowleaf balsamroot Balsamorhiza agittata (4.0%). Most forage species were ingested randomly by the bighorn sheep. High (>2.5) selection indices for rough fescue, prairie junegrass, needle-and-thread, Kentucky bluegrass Poa pratensis, Thompson's paintbrush Castilleja thompsonii, silky lupine Lupinus sericeus, pasture sage Artemisia frigida, snow buckwheat Eriogonum niveum and Wyeth buckwheat E. heracleoides, were associated with a combination of phenological patterns selected in proportions less than available. California bighorn selected forages based primarily on plant availability. -from Authors