Northern Continental Divide Ecosystem Grizzly Bear Monitoring Population Monitoring Annual Report, 2009-2010
Mace RD and Roberts L. 2011. Northern Continental Divide Ecosystem Grizzly Bear Monitoring Population Monitoring Annual Report, 2009-2010. Northern Continental Divide Ecosystem Grizzly Bear Monitoring. Montana Fish, Wildlife & Parks; Northern Continental Divide Ecosystem Grizzly Bear Monitoring Team. Kalispell MT
Reports on annual population trend monitoring within the Northern Rockies, including Glacier National Park. A program to monitor the population trend of grizzly bears in the Northern Continental Divide Ecosystem (NCDE) of Montana was initiated in 2004. The goal of this program is to estimate population trend by monitoring the survival and reproductive rates of radio-instrumented female grizzly bears. Since 2004, we have monitored the survival and reproductive output of 104 female grizzly bears. In 2009, we captured 17 females 18 times, and 17 males 20 times. In 2010, we captured 23 females 25 times, and 10 males 11 times. Including conflict males and females, we radio-monitored 109 and 98 grizzly bears in 2009 and 2010 respectively. Annual survival rates were estimated for females and males. Mean subadult and adult female survival was 0.884 and 0.923 for bears used in trend analyses. Survival rates for male bears captured for trend research averaged 0.815 and 0.862 for subadults and adults. Survival rates for management bears were lower. The ratio of reported to unreported deaths for both sexes suggest that for every 1 reported death, there were 1.46 deaths were not reported to management authorities. In 2009 and 2010, we followed the fate of 44 and 40 dependent young respectively. Home range size (95% isopleths) was largest for subadult females (x¯ = 242 km2) followed by solitary adults (x¯ = 164 km2). Home range sizes of females were nearly twice the size outside of Glacier National Park than inside. To date, we have analyzed 54 hair samples from the NCDE for stable isotope signatures. In general, we observed a higher incidence of meat in samples from the east side of the Continental Divide compared to samples from the west side. In 2010, we obtained BIA readings and actual weights on 44 grizzly bears in the NCDE at time of capture. Although samples sizes were low, mean % body fate estimates were >8% for both sexes each month. We document further expansion of grizzly bear occupancy beyond the federal recovery zone. There were 21 and 23 known/probable mortalities of grizzly bears in the NCDE during 2009 and 2010, respectively.
- Type
- Published Report
- Authors
- Mace, Richard; Roberts, Lori
- Date of Issue
- 2011-04
- Publisher
- Montana Fish, Wildlife & Parks; Northern Continental Divide Ecosystem Grizzly Bear Monitoring Team
- Units
- CRCO , GLAC
- Keywords
- crown of the continent, Grizzly Bear, northern continental divide ecosystem, Population Monitoring, Population Trend, Ursos arctos, Wildlife Studies