Five 7.3m x 7.3m exclosures were constructed on winter range following grazing. All feeding craters within the sites were permanently marked. The exclosures were later examined, disassembled and the crater outlines super-imposed on vegetation maps. The procedure was repeated on these sites the following year. The number, size and vegetation of the craters was similar in both years. The area of the site cratered was related to vegetation type and was modified in one case by snow conditions. Lichens composed 75 percent of the vegetation and included Cladonia mitis, C. rangiferina, Cetraria nivalis and Peltigera apthosa. An average of 41 percent of the sites was cratered during the two years and of the areas cratered the first year, 26 percent were reutilized. Maximum values of 51 percent and 39 percent respectively were recorded. It is concluded that lichen compose a major part of the mid-winter diet and that, on heavily cratered sites, most of the available forage is utilized in two years of intensive grazing. Differential snow accumulation, in successive years, may reduce the impact of grazing on sheltered sites.