Habitat relationships and activity patterns of a reintroduced musk ox population

Abstract

A reintroduced muskox herd in arctic Alaska was studied over a 2-year period to assess seasonal changes in activity patterns and feeding behavior. This large herd showed high calving rates and early breeding in females, characteristic of a rapidly expanding population. Age- and sex-specific differences in activity budgets reflect seasonal energy demands of the different cohorts. Comparison with high arctic muskoxen shows that characteristics of suckling behavior provide a more sensitive indicator of differences in range quality than does variation in summer activity patterns. In summer, muskoxen appear to select vegetation types on the basis of abundance and phenological stage of preferred forage species; snow characteristics strongly influence habitat selection in winter. The herd remained within a limited home range with overlapping seasonal ranges and a distinct calving area. The restricted movements and conservative activity budgets permit minimization of energy expenditure and forage requirements, allowing for a year-long existence in areas of low primary productivity.