Calf Production, Calf Survival, and Recruitment of Muskoxen on Banks Island during a Period of Changing Population Density from 1986–99

sex and age classification surveys of muskoxen were conducted during summer. We estimated calf production (number of calves per 100 females aged 2 years or more), calf survival, and recruitment (number of yearlings per 100 females aged 2 years or more). Calf production ranged from 31.3 to 56.3 and was similar between periods of increasing and decreasing density (mean = 42.3 vs. 40.8). Calf survival ranged from 23 % to 83 % and was generally higher while density was increasing than during its decline (mean = 60 vs. 45). Survival at a given density was lower following the 1994 peak in density. Recruitment ranged from 10.0 to 41.7 and was higher (p = 0.06) during the period of increasing density than during the decline (mean = 28.0 vs. 17.2). Calf survival and recruitment were lowest following two consecutive severe winters, but animal density explained more of the variation in survival and recruitment than did late-winter snow depth. There was a positive relationship between the proportion of sedge (Carex spp., Eriophorum scheuchzeri) in the summer diet and calf survival and recruitment. Patterns of calf survival and recruitment plotted against density were consistent with those modelling a density-dependent relationship. Our results suggest that severe weather alone cannot explain the fluctuations in the population dynamics of Banks Island muskoxen and that underlying density-dependen