Montana’s two early snowfalls contributed to the deaths of five grizzly bears in one week on the Rocky Mountain Front.
Those five deaths don’t include a sixth grizzly that was put down east of Rogers Pass for killing cattle, pushing the one-week death toll to six and the unofficial annual mortality count to 38 in the Northern Continental Divide Ecosystem.
Last year, a record 46 grizzly bears died in the Northern Continental Divide Ecosystem, which comprises 25,000 acres including Glacier National Park, the Bob Marshall Wilderness complex and surrounding areas.
And, 53 suffered "mortalities," which includes those that relocate themselves or are relocated out of the NCDE.
Mike Madel is a grizzly bear specialist with Montana Fish, Wildlife and Parks. He noted that the five grizzly deaths on the Blackfeet Indian Reservation last week all involved bears that were feeding on carcasses of cattle that were caught in the deep snow.
“The cattle were hit by a train on BNSF tracks and not reported. Two bears were hit by a train, and three were hit on the highway,” Madel said. It was in an area where Highway 2 is close to the train tracks. “And four were females; that’s so unusual. In my 35 years that may be the worst I have heard of in mortalities in just a few days.
“But they are super hyperphagic right now and are not hibernating just yet.”
Hyperphagic means the bears are trying to consume as many calories as possible before entering their dens for the winter.
The deaths came on the heels of a late-September record-setting blizzard in which 48 inches of snow fell in the Blackfoot Reservation area. Ranchers weren’t able to round up all their cattle prior to the storm, which led to the cows’ deaths.
Most of the snow melted, uncovering the carcasses, but about 10 inches remained on the ground when the next snowstorm moved through the region the weekend of Oct. 5-6, dropping another 10 to 12 inches in the mountains, according to the National Weather Service.
Slightly more than an estimated 1,000 grizzly bears inhabit the NCDE. The population is protected as being “threatened” under the federal Endangered Species Act. But during a visit last week on the Rocky Mountain Front with U.S. Interior Secretary David Bernhardt, Montana U.S. House Rep. Greg Gianforte discussed his efforts to make it easier to delist the NCDE grizzlies.
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Yet coupled with last year’s mortality of 53 grizzlies in the NCDE, this year’s known deaths could mean that close to 10% of the NCDE population has been removed in two years.
Cecily Costello, a grizzly bear researcher for FWP in Kalispell, said it’s far too early to say whether that’s alarming or even a trend. A lot of factors play into population estimates and mortalities, including the definition of mortality. For scientists like herself, “mortality” means a grizzly died, relocated itself, was relocated by bear managers, taken to zoos (cubs), or was moved to supplement other populations like those in the Cabinet-Yaak area.
“I haven’t really done any analysis yet; I don’t have all of the data of all of the mortalities, I haven’t looked at what’s inside or outside of the geographic monitoring area, so I can’t really say what the impact is on the population,” Costello said. “I’m not overly alarmed yet. I’m going to kind of wait and see until the year is completed.”
She notes that some of the mortalities were offspring, whose survival rate is between 55% to 75% in any given year. Costello added that at this time in 2018, grizzly mortalities in the NCDE were in the mid-40s, so this year is trailing behind that somewhat. Another factor could be the growth in the grizzly bear population is pushing them into their historic territory that people now inhabit, causing more conflicts that get the bears removed.
“I’m hoping that with all this wintry weather we’re getting, the bears make the decision to go into their dens earlier this year,” Costello said. “Usually that’s not weather-related totally, but food-related — whether or not they can continue to forage. If the snow melts off it will have very little impact. If the snow sticks around and covers the ground, the forage may make a difference.”
Madel expects females to begin hibernating within the next few weeks, followed by the males. From what he and other bear biologists have seen, the bears are in pretty good shape after feeding on the abundant berry crop this year.
Jamie Jonkel, a Missoula-based FWP bear specialist, said in his experience grizzly bear mortalities spike every few years, then drop back down so “I will not get excited about this, and will wait to see if this trend goes down.”
Information from FWP on grizzly mortalities in the NDCE since 2004 appears to bear that out, with the known and probable mortalities dropping from 33 in 2004 to 14 in 2006, then an upward trend from 17 in 2008, to 34 in 2011. Known and probable mortalities averaged in the low 20s from 2014 to 2016 before increasing to 28 in 2017 and spiking to 53 in 2018.
“I think what’s happening as the bear population picks up, we have been doing a lot of preventive work,” Jonkel said. “But some years we have a heavy mortality rate, sometimes two years in a row, followed by less mortality for the next four years.”
And while the dead cattle that drew the bears to their deaths is hard both on the ranchers and wildlife managers, the carcasses do provide an added caloric and fat boost for grizzlies overall as the berry crop wanes.
“It’s a shame they got hit by trains, but we do have a lot of carrion out there from the storm,” Jonkel said. “That will allow the bears to scavenge the carrion. It’s not good for the ranchers, but it’s good for the bears.”