• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Key words; American black bear; denning ecology; interior Alaska; northern boreal forest; reproduction; survival rates; Ursus americanus The range of the American black bear extends over; Yukon; Ursus arctos; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.525.2297; http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_13/Bertram_13.pdf

Abstract: American black bears (Ursus americanus) are common predators of ungulates in interior Alaska, yet little research has described bear demographics. This study examines movement, denning, and reproductive characteristics of a black bear population in the Yukon Flats in eastern interior Alaska. To our knowledge, this location at 66&N latitude is the northernmost study of black bears. A total of 29 ind ividual black bears were captured 53 times between 1995 and 1997. Capture rates were high with a mean annual rate of 2.3 black bears/I 0 trap days. A total of 900 telemetry locations was obtained from 23 radiocollared black bears. Mean annual home ranges for adult female and male black bears were 15.5 and 182.5 km2, respectively. The mean date of den entry was 26 September (range: 19 Sep-8 Oct, n = 42) and the mean date of den emergence was 2 May (range: 26 Apr-6 May, n = 31). Mean length of denning exceeded all previous reports at 220 days (range: 213-229 days, SD = 4, n = 31). Females excavated all dens in well drained terrain in forested areas. Mean litter size for 7 adult females was 2.1 (n = 10). The recruitment and reproductive intervals were 2.0 years (n = 2) and 1.6 years (n = 5), respectively. The survival rate for cubs weaned to 1 year was low (0.45). The mean annual survival rate for adult males was 0.86. We report 2 likely instances where, during spring, grizzly bears (Ursus arctos) preyed on adult female black bears with young.