Black Bear Population and Stability
The Results: Total population of bears in the park is estimated to be 20-24 bears.Investigators captured and radio collared a total of 14 bears. Of these bears, four were adult males, four adult females, two subadult (one to three years) males, and four were subadult females. Remote cameras in the park identiﬁ ed ﬁ ve additional bears on the west side of the Continental Divide and six on the east side. Coupled with visitor reports of bear sightings, the minimum population of black bears in the park is between 20 and 24. The team documented four mortalities during the study, with two occurring through legal harvest on adjacent properties, while causes of the other two mortalities were unknown. The resulting survival rate for all bears from 2003-2006 was 93%. Sixteen cubs were observed during historic and contemporary studies averaging 1.8 cubs/litter. In the 1985-91 study only 43% of cubs in the park survived. However cub survival during this study was 71%.
Although the study found that black bears in the park still had one of the lowest densities ever recorded, it suggested that the population could exhibit substantial growth in the next 10 years. Also bears in the park have become heavier and are in better nutritional condition since the 1985-91 study, possibly due to increased use of anthropogenic
(human) food sources. This is also suggested by the fact that bears are incorporating more human-use areas in their home ranges than in years past. However bears that become habituated to human foods can become more aggressive in their eﬀ orts to obtain these food sources, and this situation usually results in the euthanization of problem bears.
This summary is based on published, peer-reviewed and/or unpublished reports available at the time of writing. It is not intended as a statement of park policy or as a deﬁ nitive account of research results. For more information on the park’s research program, see www.nps.gov/romo
Written by: Darin Newton Date: June 2007 Updated: January 2008 Photo credit: NPS-RMNP