Introduction of muskoxen in northern Quebec: the demographic explosion of a colonizing herbivore

Abstract

Between 1973 and 1978, 42 muskoxen (Ovibos moschatus), mostly immature, were released northwest of Kuujjuaq, along the south shore of Ungava Bay. Helicopter censuses, complemented by ground observations, were conducted over 725 km 2 in 1983 and 1986: 148 and 290 animals were counted during the first and second surveys, respectively. The finite rate of increase of the population averaged 1.25 during the 3-year interval; that rate indicates high fecundity and low mortality, because the maximum finite rate of increase is 1.30 if all animals survive and if females first calve at 3 years of age and thereafter produce one calf each year. Ground observations confirmed a high productivity: calves constituted 26 and 23% of the population in 1983 and 1986, respectively; in terms of calves per 100 mature cows, the respective ratios were 97 and 86. Some animals dispersed up to 650 km from the area of release; populations may be establishing themselves in new locations. Muskoxen are now well established in the tundra of northern Quebec.