Grizzlies Thriving in Montana

By Matthew Frank, 9-17-08

	Caption: Scroll down for a video

That federal study of grizzly bear DNA in Montana criticized by Republican presidential candidate John McCain as pork barrel spending has been released, and it concludes that there are 765 bears in northwestern Montana, the largest population of grizzly bears documented there in more than 30 years, and a sign that the species could be at long last rebounding, the AP reports.

From the USGS press release about the Northern Divide Grizzly Bear Project:

Scientists designed a comprehensive study plan that involved non-invasive methods of collecting hair from bear rubs (bears naturally rub against trees and posts) and systematically positioned hair traps that made use of scent lure to attract bears. During the 2004 summer field season, 4,795 bear rubs and 2,558 hair traps were used to collect hair. Approximately 13,000 samples were collected from bear rubs and 21,000 were collected from hair traps, providing researchers with a total of 34,000 bear hair samples.

Through the use of genetic analysis, including DNA fingerprinting, researchers were able to determine the total number of bears sampled and track their detections in time and space. Genetic analysis of the 34,000 hair samples resulted in the identification of 563 individual grizzly bears. USGS scientists then used statistical models to calculate the number of bears not sampled and incorporate them into an estimate of the total population size, leading to a complete population estimate of 765.

“Based on our field studies and state-of-the-art genetic analysis, we are confident that our estimate of 765 grizzly bears residing in the study area in 2004 is solid,” said Kate Kendall, USGS Scientist and lead researcher on the project. “This is two and a half times the number of bears previously estimated to live in the area.  The new information will allow us to better evaluate mortality rates.”

Researchers were also able to examine the gender, genetic health, and amount of occupied habitat of the grizzly bear population.  Based on field studies and genetic analysis, scientists estimate that 470 of the 765 bears are females and data indicates that females are present in all 23 bear management units within the study area. The number and wide distribution of females indicates good reproductive potential.

The study also found that the occupied range of the grizzly bears now extends 2.6 million acres beyond the 1993 recovery zone boundary set by the U.S. Fish and Wildlife Service in the Grizzly Bear Recovery Plan.

The USGS has made available on its site a number of videos of bears rubbing trees and other animals caught on remote camera boxes triggered by motion sensors in Glacier National Park (including eight wolves strolling past). Here’s one grizzly enjoying a good scratch: