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Some insight into Griz-Human conflict in Yellowstone
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David Chenault
(DaveC) - BPL Staff - F

Locale: Crown of the Continent
Some insight into Griz-Human conflict in Yellowstone on 08/10/2010 09:13:46 MDT Print View

It's been a bad year thus far for human-griz conflict in the Yellowstone area. Besides the fatal Soda Butte mauling, there have been four bears in the park that have been moved to other locations, typically the last resort before they're shot.

I got this last bit Sunday from a bear management specialist at the Heart Lake patrol cabin. My wife and I were out dayhiking, and on the lakeshore came across a sign saying that all of the backcountry sites on the lake had been closed that morning due to bear activity, and that backpackers planning to stay there should hike out or consult the ranger about a different site. Apparently late Thursday evening/early Friday morning a Griz had put its paw through a tent at 8H5, one of the sites near the Mt. Sheridan trail. The rangers cleared everyone out, confirmed via tracks and scat that the bear was indeed returning to campsites, and called in the bear management team. They had set up an electrified tent to shock the offending bear, and were prepared to haze it further with (I presume) flare shells and rubber bullets. The management guy mentioned they also have an electrified food sack to condition bears that try to climb the food poles.

Interesting as it was to get insight into the aversive method used to condition problem bears, most enlightening was the ensuing conversation about why so many conflicts have happened this year. This is particularly relevant because resarch from the Interagency Griz team, which I cited in the Soda Butte thread the other week, has shown that the overwhelming majority of hiker-bear conflict happens during hyperphagia, the time in late August and September when the bears are going crazy stuffing themselves and roaming all over looking for more food. I think folks at Yellowstone are justifiably concerned.

Yellowstone had a quite mild winter, with respect to temperatures and especially to snow. This was followed by a cold and wet spring, the light snowpack took longer than would be typical to melt off. The bear management ranger said that one result of this was that their spring transects counting winter-kill elk and bison found that very, very few animals had died over the winter. This is the main food source for Griz when they first wake up in the spring, and thus strike one. Strike two was that the cold spring kept many of the most nutritious plants from budding out (Griz don't leach nutrients out of plants as effectively as ungulates in the area, and are thus usually more selective with their veggies), and delayed the fish spawning runs. Yellowstone Lake was still totally frozen in mid May. A speculative strike three (my theory) is that the late spring actually gives a net benefit to the migratory animals upon which bears pray (usually elk calves). They can delay their migration, and get higher quality forage later in the summer (things were still spring green this weekend), thus the bears and weak and the prey animals stronger. Perhaps. The fourth strike that is coming up is that the mild winter will be bad for the Whitebark Pine nut crop, the single most significant source of fall calories for Griz in Yellowstone.

While it's impossible to demonstrate a significant correlation with only one seasons data, the apparent significance observable thus far this year is hard to ignore.

As I've mentioned elsewhere, my wife and I are planning our next Yellowstone trip to the Bechler area in a month or more. We're waiting for the (awful) bugs to die, and the Bechler area is very nice in early fall. It is also the quadrant of the park with the least dense Griz population, and thus will minimize the chance of user conflict. We'll also look to recruit another person or two, as larger groups have never had backcountry bear issues in Yellowstone.

Some food for thought. If you're in the park and ask at the Mammoth Ranger Station, they have quite a few summaries of the research on bear behavior that they'll give you. The interagency team also has loads of full text publications on their website.

Doug I.
(idester) - MLife

Locale: PNW
Re: Some insight into Griz-Human conflict in Yellowstone on 08/10/2010 09:59:41 MDT Print View

Fascinating post David, thanks!

David Olsen

Locale: Steptoe Butte
Data on other predators on 08/10/2010 11:26:48 MDT Print View

I wonder if there are other predators effected by some of
these conditions? Wolves, cougars, weasel family, coyotes,
bird of prey?

Could their behavior be used in predictions of bear behavior
or visa versa?

David Chenault
(DaveC) - BPL Staff - F

Locale: Crown of the Continent
re: other predators on 08/10/2010 13:10:36 MDT Print View

Dave, I would imagine predictions could be made along those lines, if data is available. It probably exists on wolves, but not other animals. Bears have been so heavily studies for the last half century.

The wolves in Yellowstone like winter, they seem to have the best success rates. A light winter might mitigate that advantage, though on the other hand the differences in snow accumulation might not impact their hunting. It seems more likely it would effect game distribution (more bison and elk stay in the park), which would have some effect.

Interesting stuff to think about.