Muskox-Caribou Summer Range Relations on Banks Island, N.W.T.

Abstract

The use of food and space by muskoxen (Ovibos moschatus) and Peary caribou (Rangifer tarandus pearyi) in north-central Banks Island [Northwest Territories, Canada] was studied in summer 1973 to ascertain whether interspecific competition was occurring. The distribution and dispersion of the 2 ungulates overlapped only negligibly and their preferred habitats and diets were correspondingly different. Muskoxen foraged mainly in wet habitats, where they ate almost exclusively lush sedges (Carex stans), supplemented by grasses and willows (Salix spp.). Caribou were concentrated in sparsely vegetated uplands and ate moderate amounts of small sedges (Carex spp.), grasses, willows, and milk-vetch (Astragalus alpinis). Measurements of carcass fat, marrow fat, and rates of production and survival of young indicated that both ungulates were in good physical condition. Competition was apparently not occurring.