O. c. canadensis are BLUE-listed because their winter ranges are threatened by past overgrazing, competition with domestic stock and other ungulates, land alienation and human encroachment. They are also threatened by disease, particularly those transmitted by domestic sheep. Ecology Wild sheep are predominately grazers, relying on grassland habitats. Breeding occurs in November and usually takes place on high, grassy slopes of the winter range. Ewes give birth to lambs from April-May on rough, rocky escape terrain adjoining the winter range grasslands.
Some bighorns are migratory.
Bighorns are not territorial. Distribution California bighorn sheep are scattered in small herds on the mountains and grasslands of the Ashnola River system, the east side of the South Okanagan valley in the vicinity of Vaseux Creek, Shorts Creek west of Okanagan Lake, the Fraser River basin from Lillooet north to Williams Lake, the upper Taseko and Chilko Rivers and an isolated herd on Far Mountain, north of Anaheim Lake. Two herds have been established near Kamloops Lake and Grand Forks following transplants. Rocky Mountain bighorn sheep are found primarily in the southern Rocky Mountains and Rocky Mountain Trench east of the Columbia River, from the 49th parallel north to the Blaeberry River. Smaller herds are located between the Blaeberry and upper Wapiti Rivers.