Gilbert's Grizzlies

The grizzly lives on berries, nuts, meat and fish both fresh and dead, insects, bulbs, eggs, and whatever else its incredible nose leads it to. "Increasing the food base would maintain large numbers of bears on relatively small pieces of land," says Gilbert. "We wouldn't have to wage political battles over attempted land acquisitions by the government, which people would resist."

Loaded for bear: Gilbert and his trusty telescope. Brian Atkinson.

He recommends that agencies like the U.S. Forest Service and the National Park Service start by establishing whitebark pine plantations, which would not only provide bears with pine nuts of a nutritional quality on par with salmon but could also help control avalanches and erosion. Gilbert says he believes bears would benefit from the restoration of serviceberry, chokecherry, and other shrubs. In much of the Rockies, intense browsing by sheep, cows, elk, and other animals has virtually eliminated these plants. "It would take a long time," he says, "but the Forest Service and other land managers--including private landowners--could do the bears a great favor."

Humans in the Rockies have competed for bear food, too, says Gilbert. "For a number of years, anglers in the parks were taking a thousand pounds of trout or more a year," he says, applauding the recent shift to catch-and-release fishing and new rules on the size of trout that can be kept, both of which have led to a recovery in the trout population. "I've argued that we ought to cut back on the angling because the bigger the trout, the farther upstream they go, and the more vulnerable they are to bears. The beauty of the trout is that bears feed on them in relatively remote areas, so it draws them away from conflict zones around towns."

He has also suggested weirs (low dams) and artificial falls on Yellowstone Lake's tributaries to make the unwanted sucker fish available to bears, but he got a flat "no." "The Park Service tolerates many artificial things like fishing, but when you propose something else artificial that would balance it, like a simulated dam, they're against it. It's hard to see how the bears are getting a fair shake when the government can't stop the negatives but won't introduce positives as a balance."

Having said that, Gilbert does point out a positive. "I do think that in recent years the Park Service has been doing a much better job of managing bears and educating people," he says. "They teach visitors to stay in their cars, and they're more tolerant of bears near roads--which are often built through some of the best wildlife habitat."

Anyone who has attended lectures or seminars with Gilbert knows that he will listen to every word and then he will ask questions--hard questions. He is opinionated, and he'll pounce firmly if he believes such confrontation would improve knowledge. He is a good person to talk to about the role of advocacy in science.

Fishing expedition: salmon jump for dinner. Barry Gilbert.

"My general sense is that scientists withdraw far too much; they almost use objectivity as a shelter to get away from controversial issues. There are incentives to withdraw. You might be told you're a popularizer, you're an advocate and not a scientist. It's almost as if there's a social hierarchy based on how pure you are compared to the purity of other scientists. The American public is generally poorly educated in science, but the public has paid considerable amounts of money to educate many of us. I think we have an obligation to be involved in these issues and to get the information out. If it's political, well, so be it."

Politics or no, Gilbert believes grizzly bears are important, and he continues to broaden his research. Lately, he's been interested in the role of bears in keeping forests healthy. It sounds backwards somehow: How could trees benefit from bears?

Recall the prodigious appetites of those bears that gather for the salmon runs, and consider that trees near salmon-filled rivers in Alaska grow faster than trees near rivers with few fish. The reason appears to be that bears that gorge on salmon spend their resting hours in the woods, where they leave nitrogen in the form of scat and urine and half-eaten fish. Gilbert speculates that this transport of fertilizer "may constitute the largest such transfer to mountain forests and streams ever known." He is determined that such a good deed will not go unnoticed.

"It's a very exciting chance to study how bears provide crucial services in the nutrient cycle of forests," he says. "The best forest research suggests that the temperate rainforests are utterly dependent on inputs of nitrogen and phosphorus to maintain their growth." His main goal is to provide "better science" to help environmental organizations protest hunting quotas and halt the destruction of old-growth forests, especially the rainforests of coastal British Columbia.

Along the Koeye River in British Columbia, Gilbert and graduate student Arthur Morris have collected hundreds of samples of soil and plants and bear scat from areas where bears were taking salmon. Working with John Stark of Utah State's biology department, they've compared these to other samples taken near streams where bears weren't active. "We were there when the bears were there," Morris says, "and we had to worry constantly about staying out of their way."

Morris and Gilbert wanted especially to know how much nitrogen in the forest could be linked to the fish. This involves a laboratory procedure that any detective would love. Nitrogen molecules, it happens, have a couple of different stable forms in nature. The more common one is abbreviated as N14, meaning it has an atomic mass of fourteen. The other form, N15, has a slightly different structure. Both are found throughout the planet, but the proportions vary depending on where you look. In the oceans, and thus in the bodies of salmon, the level of N15 is usually higher than in fresh water and on land.

Morris checked his samples for N15 using a specialized mass spectrometer in Stark's lab at Utah State University. He found that, indeed, the so-called "signature" of N15 was strongest near bear trails and around bears' bedding areas in the forest near streams where bears were fishing. The results were not precise enough to say exactly what percentage of the forest's nitrogen comes from fish, but in some places it could be more than 25 percent. "We've added a piece to the puzzle," says Morris. "We've definitely helped establish the link between the ocean, the river, the bears, and the forest."

Being with bears: wise, above, and unwise ways of observing, below. Barry Gilbert.

Another graduate student, Owen Nevin, is using computer modeling to find out if bear population densities can be predicted by measuring food supply. With such a model, says Gilbert, "We can look at the access to and abundance of fish along the coast and predict what the density of bears will be." Such information would not only help wildlife managers handle bears less (less trapping, marking, and radio-collaring), but would also help them decide the sizes of proposed bear reserves.

Large reserves with plenty of food are the only means, it seems, to protect this big and toothy fellow predator from extinction, at least in the lower forty-eight states. This animal, which in adulthood can drag 1,200-pound moose carcasses uphill, eat twenty-three salmon in ninety minutes, or feast on 200,000 berries in a day, cannot seem to withstand human encroachments any more than a 200-year-old oak tree can withstand a chainsaw. Even on the Brooks River in Alaska, where the bears are healthy and food is plentiful, certain bears will not come to water if people are nearby.

Tamara Olson, a former graduate student of Gilbert's who is now a wildlife biologist, found that these "nonhabituated" bears are the most likely to charge people if they feel threatened. After such an encounter, the bear often leaves the area. While this may not affect the survival of an Alaskan bear with room to roam, it would almost certainly shorten the life of a bear in the Rockies. Bears tolerant of people, the habituated ones, are also at risk: If they learn to associate food with people, they are much more likely to approach camps, cabins, and other places where they could be killed.

Given a choice, bears will usually avoid people, and cubs will learn this avoidance from their mothers. In fact, bears are very sophisticated in terms of what behaviorists call "social learning"--the ways they share knowledge. Cubs spend up to three-and-a-half years with their mothers, learning what to eat, where to find it, how to hunt, and what to fear. After they leave their mother, siblings will sometimes stay together for a while, sharing more of what they learn about the world.

"It strikes me that in some ways bears resemble chimpanzees, behavior-ally," says Gilbert. "They learn highly individualistic behavioral traits for catching fish or other food, and we see these techniques being passed down through generations, almost like traditions. The classic example is from McNeil River, where a particular mother bear always fished in the same place, with her right paw cocked above the water. In later years, her grown cub came back to that exact spot, and stood on the same rocks with her right paw cocked, too."

Bears also seem to have excellent memory. Olson found that one adult female grizzly returned to the Brooks River salmon run on the same date three years in a row. Other bears in Alaska are known to swim ten miles out to sea every year at the same time to gorge on eggs at an island seabird colony.

Gilbert often surprises people by expressing his hope that the bear that attacked him continued its life undisturbed by man. The observation towers where he has spent so much time have elevated him physically above grizzlies, but they have not diminished his admiration for them, or his fear, or his concern that bears are properly managed. "Would the West be the West without grizzly bears? I doubt it." With Gilbert and his students working on their behalf, the species may stand a better chance of surviving.

Jackson is a freelance writer in Durham.