Grizzlies hear 'dinner bell' when hunters move in, researchers say

By SCOTT McMILLION, Chronicle Staff Writer

Hunters who talk about "dinner-bell" grizzly bears just might have a point, says a study by a group of carnivore researchers who work in and around Yellowstone National Park.

When hunting season opens, grizzly bears move in, according to the results of the study to be published shortly in the Wildlife Society Bulletin.

The researchers monitored radio-collared grizzlies, wolves and cougars in the park's northern range and in the Absaroka Beartooth Wilderness Area, just north of the park.

The project's goal was to see how those predators react to the presence of human hunters.

Although the work looked at limited numbers of animals, it found evidence that elk hunters lure grizzly bears outside the park.

The study looked at only two bears, and only during the late summer and fall of 1999. But its findings indicate "grizzly bears shifted north of the boundary once hunting began."

Cougars, on the other hand, tended to leave the wilderness and head for the park once large numbers of hunters arrived. That might be because elk herds also tend to move away from hunters, the study says.

Wolf behavior didn't change much when hunting season opened.

"Our findings for grizzly bears were not unexpected," wrote the study's authors, 10 scientists from the National Park Service, the U.S. Fish and Wildlife Service, the U.S. Forest Service, the Montana Department of Fish, Wildlife and Parks, Montana State University, and the private research groups Wildlife Conservation Society and Beringia South.

They cited other studies that show hunters leave behind as much as 500 tons of guts, bones and discarded meat every year in the greater Yellowstone area.

That much food is a big motivator for grizzly bears, especially since hunting season coincides the hyperphagia, a sort of feeding frenzy that grizzly bears enter before they take to their dens in the late fall or winter.

That means hunting season, by its very nature, sets up encounters between well-armed people and food-focused bears, sometimes with disastrous consequences.

"Numbers of hunting-related grizzly bear moralities increased in the (Yellowstone area) during the 1990s and nearly half this increase" came during early season hunts in September.

The situation "may be exacerbated by an increasing and expanding grizzly bear population."

It isn't good news for people, either.

"Human safety may be compromised by interactions with carnivores attracted to discarded elk parts and hunter camps," the study says.

There are as many as 70 hunting camps in the area when the season opens.

Bears apparently have learned when hunting season starts, just as they learn when fish use spawning streams and when berry crops ripen. Their movements to hunting zones "were correlated with the opening of hunting seasons."

More than half of all grizzly deaths and human injuries occur during big-game hunting seasons, according to statistics compiled by Kevin Frey, an FWP bear specialist.

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