The number of grizzly bear deaths declined by more than 50 percent this year in the greater Yellowstone ecosystem, according to the Interagency Grizzly Bear Study Team.
The numbers are particularly notable because trees produced fewer than normal whitebark pine cones, an important grizzly bear food. Grizzly bears’ reaction to declines in whitebark pine cones will help determine if the bear is removed from the endangered species list.
Twenty-four grizzly bears have died so far in 2013 compared to 56 in 2012. Rates of females with cubs are also high this year, said Frank van Manen, leader of the grizzly bear study team.
It’s risky to draw long-term conclusions from one year’s numbers, van Manen said.
“These systems are complex, and there are a lot of interrelations we can’t predict,” he said. “This isn’t a trend, but it is a noteworthy observation.”
The Yellowstone ecosystem did have a large crop of berries, which helped provide additional food, he said.
The interagency study team will present its paper on how grizzly bears respond to changes in available food at a Yellowstone Ecosystem Subcommittee meeting Wednesday and Thursday in Bozeman, Mont.
Conflicts between grizzly bears and humans are also down this year in Wyoming, said Dan Thompson, large carnivore section supervisor for the Wyoming Game and Fish Department. He in part credits continued education on how to bear-proof food while recreating in the backcountry.
Hunters are generally responsible for the largest number of bear deaths, but were second to livestock conflicts this year, van Manen said.
Grizzlies injured two people in Wyoming and two people in Yellowstone National Park in 2013.
Bear deaths from 2013 are not final since grizzlies are still active. They should begin hibernating soon.
The U.S. Fish and Wildlife Service removed grizzlies from the endangered species list in 2007. A federal judge put them back on the list in 2009 because of several concerns including the future of whitebark pine, which is dying from blister rust and the mountain pine beetle.
An appeals court dismissed some of the concerns in 2011 but upheld the whitebark pine ruling. The court told the Fish and Wildlife Service it needed to know more about bears’ reaction to the tree’s decline before grizzlies could be removed.
If the interagency study team reports that plentiful whitebark pine is not critical to grizzly bears’ survival, the Fish and Wildlife Service could move toward a delisting proposal. The Fish and Wildlife Service likely will not make a decision on a delisting proposal until late December or early January, said Chris Servheen, the service’s grizzly bear coordinator.