POPULATION TREND OF THE YELLOWSTONE GRIZZLY BEAR AS ESTIMATED FROM REPRODUCTIVE AND SURVIVAL RATES

The trend of the Yellowstone grizzly bear (Ursus arctos horribilis) po pulation was estimated using reproductive rates calculated from 22 ind ividual females and survival rates from 400 female bear-years. The poi nt estimate of the rate of increase was 4.6%, with 95% confidence limi ts of 0 and 9%. Caution in interpreting this result is advised because of possible biases in the population parameter estimates. The main pr ospects for improving present knowledge of the population trend appear to be further study of possible biases in the parameter estimates, an d the continued use of radiotelemetry to increase the number of sample s on which the estimates are based.