Black bear (Ursus americanus) research was conducted from 1983 to 1992 in northwest Montana. During this period 319 individual black bears were captured, of which 177 were adults ≥5 years old. Forty-eight of the adult bears were fitted with radio transmitters. Capture information and radio monitoring indicated that the age of first successful reproduction was ≥6 years old, mean litter size was 1.75 cubs, and the mean interval between litters was 3.2 years. Based on this information, a minimum sustainable annual survival rate of 0.88 was estimated. Estimates of survival using the Kaplan-Meier procedure for adult bears ≥5 years old were 0.73 for males (n = 21) and 0.79 for females (n = 27). Hunting was the single largest source of mortality for males. Hunting and illegal mortality were equally high for females. Levels of mortality and potential sources of bias are discussed.
- Volume 9
- Issue
- Pages 223-230
- Publication Date 1 January 1994
- DOI 10.2307/3872705
- File Size 320.56 KB
- Download