The truth about the gray wolf

ISLE ROYALE - From an old and sagging log cabin on this island in the cold reaches of Lake Superior, Rolf Peterson and dozens of other biologists have made history and put to rest many of the persistent and wrongheaded myths about the island's most famous resident: the gray wolf.

Peterson is a wildlife biologist who is the latest researcher working on what has become the world's longest predator- prey study. Since 1970, Peterson has studied the relationship between wolves and moose on Isle Royale. He was just 9 years old when the research started in 1959. Eisenhower was president and Ford had just released the Edsel.

The long years of study have provided not only a wealth of information about the intricate connections between these two majestic mammals but also considerable insight into the relationship of the endangered gray wolf to the landscape in other northern states, including Wisconsin.

Peterson's research, in fact, is proving a crucial tool for wildlife ecologists in Wisconsin as they fight an intensifying battle against misinformation about the timber wolf. Since the early 1970s, when wolves had nearly disappeared from the state, Wisconsin's wolf population has rebounded to about 450 animals.

Adrian Wydeven, the wildlife ecologist who heads the state's wolf program, said the Isle Royale studies have provided considerable information for the Wisconsin recovery effort. Most important, he said, have been accurate descriptions of wolf behavior to counter the long-held myths about wolves that are often perpetuated by those who are against the return of the predator to the state's forests.

"Isle Royale," said Wydeven, "represents the beginning of modern wolf research. The length of the study alone is valuable. We've gotten a lot of useful information and I think those studies are becoming even more important."

To Wydeven, the studies are about truth-telling in the face of heightened criticism of wolves in Wisconsin. He cited, for example, a recent article in the Ashland newspaper titled "Wolves Threaten Our Northland Economy" that said wolves kill too many deer and frighten people.

On Isle Royale, science is bringing the wolf out of the shadows of lore and history. It is an ideal laboratory because of its insular population of wolves and moose. Moose swam to the island, perhaps in the early 1900s. Wolves crossed to the island on frozen Lake Superior in the late 1940s.

Years of patient tracking and observation have shown that, while it certainly is a deadly efficient predator, the gray wolf is an integral part of a natural web that is far more complicated than was once believed.

Peterson and other Isle Royale researchers have found that seeing the wolf's role clearly, unclouded by myth, can help us better understand a landscape in its entirety, from the ups and downs of its animal residents to the fate of a cedar swamp.

This is the view that has coalesced from the cluttered environs of the famed Bangsund Cabin on the rocky shore of Isle Royale's Rock Harbor. In 1970, Peterson, now a professor of wildlife ecology at Michigan Technological University but then a graduate student, first came to the cabin. He brought his wife, Candy, and together they started studying the bones of moose to better understand the secrets of wolf predation.

Inside the cabin is a pleasant jumble of old and comfortable chairs, wooden cabinets with doors askew, a table covered by a map of the island, a small kitchen stocked with battered pots and pans. Photos and clippings and headlines line the walls, a faded record of the many summers the Petersons have spent here. They watched their two boys grow up during all those seasons of research.

Candy, hosting guests one recent fall afternoon, served coffee from a tin pot atop the wood stove along with fresh- baked cinnamon bread. She recalled those early days, the joy of the wild island and of being close to the wolves.

"I remember feeling that they were all around us," Candy said. "Being here in the cabin allows the wolves to live right here near us. We can be a part of it all . . . It's just an absolute privilege to be here."

Outside, the yard of the cabin is littered with moose bones - vertebrae and ribs and leg bones and backbones. They are from years of collecting. Many are labeled. A shed behind the cabin is filled from floor to ceiling and from wall to wall with moose skulls and antlers, interlocked in a puzzle of white bone. All of the bones tell a story; they are a calcified history of moose on Isle Royale.

"Ecology is actually a historical science," Peterson said as he displayed several of the skulls he's collected over the years. "That isn't really appreciated. What we're trying to do is understand the past."

What are the lessons of history and bone? One of the most important findings, Peterson said, is that wolves are not indiscriminate killers. Instead, a study of the bones and teeth from wolf kills showed that the wolves prey primarily on the very old moose as well as on the sick and the young calves - these, after all, are the moose that are easiest to bring down. As Peterson pointed out in his 1995 book, "The Wolves of Isle Royale," old moose were the wolves' "bread and butter," comprising about 85 percent of their diet.

There is more to this, studies on Isle Royale and elsewhere show, than meets the eye. By culling the weak and the sick from the moose herd, Peterson said, the wolves are actually serving as agents of positive change, assuring that the prey population remains healthy over future generations because only the strong and robust moose survive to rear young. As Darwin explained, nature selects for those characteristics that give a species its best shot at surviving and prospering.

This important phenomenon happens in Wisconsin, too, though wolves are not nearly as major a predator on deer as people are. Wolves kill between 8,000 and 9,000 deer a year, according to Wydeven. People kill five times as many with their cars. Hunters kill more than 300,000 deer each year.

But Peterson said wolves, even in a place such as Wisconsin, can exert a positive influence on the overall health of a prey population. "Wolves," Peterson said, "are probably having an effect on deer all across the upper Midwest."

Peterson even speculated that wolves could play a role in stemming the spread of chronic wasting disease because of the same process of selection.

The long study of the relationship between wolves and moose on Isle Royale provided numerous surprises along the way, according to Peterson.

One of those involved the impact of wolf numbers on the health of the forest. It's a simple thing, really, but something that shows the truth of nature being dependent on myriad connections.

Data through the decades of the 1960s and 1970s showed that wolves were the major force keeping moose in check. During that same time, there was a major regrowth of the forest on the island, especially balsam.

Similarly, in the 1990s, when moose numbers climbed again, the growth of woody vegetation was suppressed. The connection, once the changes in the forest were documented, was easy to make. Moose eat young trees. Wolves eat moose. More moose mean fewer trees while fewer moose mean more forest growth.

"Growth rates of balsam fir in the forest understory," Peterson wrote in his book, "cycled in synchrony with the wolf population. When wolf numbers were high, the forest grew. What an impressive achievement for a couple of dozen wolves that were just doing what comes naturally!"

Such a finding is of special interest to Wisconsin biologists these days, according to Wydeven. Studies by researchers such as the UW-Madison's Don Waller have shown that deer are decimating the understory of Wisconsin's northern forests, especially cedar swamps. So studies are under way, Wydeven said, to understand the relationship between wolf predation and plant growth in Wisconsin's forests.

If Isle Royale is any indication, the future of the cedar in northern Wisconsin could be dependent on the success of the wolf as a predator.

The wolves and the moose on Isle Royale have communicated myriad other secrets about our world over the years. In his book, for example, Peterson told the story of how the moose on the island even gave us important and unexpected information about carbon dioxide and climate change.

Back in 1989, Peterson said, when scientists were using the Oxford University's accelerator mass spectrometer to date the Shroud of Turin, the next fellow in line to use the instrument was a geochemist named Jeffrey Bada. He carried small vials of gaseous extracts from Isle Royale moose teeth.

Bada, Peterson continued, found that moose teeth store carbon. More extensive study of 75 years worth of Isle Royale moose teeth, Peterson said, showed a steady increase in carbon, further proof of an inexorable rise in carbon dioxide due to worldwide combustion of fossil fuels.

Such unexpected findings lead Peterson to speculate about what mysteries could be solved in the future by the data that continue to be collected on the island.

I liked this rendition better (long story short, with the exception of a (suspected) pair of wolves traveling across a frozen Lake Superior (how often does that happen?) the island is a ecosystem unto itself. No moose or wolves are imported or migrate there. That is a kinda cool aspect to the story.) Please note the last paragraph

http://www.nwf.org/nationalwildlife/article.cfm?issueID=35&articleID=589

NATIONAL WILDLIFE MAGAZINE
Dec/Jan 2001, vol. 39 no. 1

Watching Wolves On a Wild Ride
By Les Line

For 25 winters, researcher Rolf Peterson has tracked the turbulent twists and turns in the lives of Isle Royale's top predators and preys
Cover

There are always surprises waiting when Rolf Peterson returns to Isle Royale National Park to spend the dead of winter in the company of the world's most famous gray wolves and the moose that are their bread and butter.

For 25 years, Peterson, a wildlife ecologist at Michigan Technological University, has led what is believed to be the longest-running study anywhere of a top predator and its primary prey. The project began in 1958 under the direction of the scientist's late mentor, ecologist Durward Allen of Purdue University. Allen saw Isle Royale, which is located in Lake Superior, as a natural laboratory, effectively isolated from human impact. Here scientists could count wolves and moose and study their interactions over time.

In the project's early years, when nearby states still paid bounties for dead wolves, coyotes, foxes and other carnivores, the researchers' findings were portrayed by wildlife conservationists as magical examples of nature in harmony. Park visitors learned from biologists' lectures how wolves culled the old and infirm from the moose herd and kept the forest from being overbrowsed. And the Isle Royale story, told in popular magazines, played an important role in changing the public's attitude toward Canis lupus.

But in Peterson's time in the early 1980s, the Isle Royale wolf population reached an all-time peak only to soon crash to the point where it appeared to be on its way to extinction. And in the absence of normally heavy wolf predation, the scientist watched the park's moose population explode and devastate its main winter food supply, the island's balsam fir stands. Recent winters have been especially tumultuous, with a catastrophic collapse of moose numbers and with wolf numbers on a roller-coaster ride.

In documenting these events, Peterson and his colleagues have shown that the Isle Royale ecosystem, despite its remoteness, is not totally immune to outside influences. In particular, introduced disease and extreme, short-term weather shifts have had far-reaching impacts on the balance between predator, prey and the environment.

Isle Royale is a 45-mile-long, 9-mile-wide island (with some 100 satellite islands and islets) that lies much closer to Superior's Ontario shore than the great lake's Michigan side. The sparse crowd of 17,000 visitors that arrives by boat during the three-month summer season commonly encounters moose along the wilderness park's trails, but only a dozen or so hikers a year will be lucky enough to see a wolf. "Isle Royale is the safest place in the world for wolves," says Peterson. "They have very little contact with people, and they're terrified of us."

From October to May, the island is uninhabited except for the seven-week period beginning in mid-January when Peterson and a changing cast of field assistants and Park Service personnel are in residence.

Neither moose nor wolves occupied Isle Royale until the last century—at least in historic times. Indian tribes hunted, fished and mined copper there for 4,000 years, but archaeologists have found no moose bones at their campsites. Peterson thinks the big ruminants, which are strong swimmers, first crossed the 20-mile-wide channel from Canada around 1900.

On Isle Royale, moose found a bountiful supply of food, and their numbers exploded. By the 1920s, several thousand were munching away at the vegetation. The island was in state and private hands at the time, and when the noted biologist Adolph Murie arrived in 1929 to do a field study, he discovered that the forest was in desperate shape, and he predicted a disaster. By 1935, the moose population was down to a few hundred starving animals. The herd recovered only because the next summer fire burned 20 percent of the island and created a new forest. But by 1945, five years after Isle Royale became a national park, moose numbers again had grown to the point where winter starvation occurred, prompting calls for control measures either through hunting or by introducing wolves.

Then in the winter of 1949, nature intervened. Bold wolves—probably only a mated pair—made a run over a solid ice bridge between Canada and the island. It was an extraordinary event. "The weather has to be cold and calm enough for the lake to freeze over," explains David Mech, a U.S. Geological Survey biologist who was Durward Allen's first graduate student on the wolf-moose study. "Then you need wolves predisposed to make a long trek over the ice," Mech adds. "The chances of this happening are pretty remote, or Isle Royale would have had wolves before the 1940s."

Those pioneering wolves and their offspring found a well-stocked larder on the 210-square-mile island. Calves and elderly animals are a pack's main prey. "Few moose between the ages of two and eight are killed by wolves," says Peterson. "Prime-age moose are too dangerous to approach. They commonly stand and pugnaciously face the wolves, which take the cue and leave. To my knowledge, no one has ever observed wolves killing a moose that did not run when first confronted by its predators." The front legs of a 900-pound moose are formidable weapons. Peterson once watched an old and blind bull stand its ground against a wolf pack for three days until the hungry canids decided to look elsewhere for a meal.

By the winter of 1960, two years into Allen's study, there were 22 wolves on Isle Royale while the moose count was 575 and climbing. In 1970, researchers found 20 wolves and 1,430 moose. Over the next decade, however, an astonishing buildup of wolves occurred, with five packs (normally there are three) totaling 50 animals hunting the island in the winter of 1980. Meanwhile, the moose population declined, and a pattern had emerged: Predator and prey were cycling in tandem, with the wolves peaking ten years after the moose herd, at a point when there were a lot of aged animals.

But by 1982, that balance was broken. Isle Royale wolf numbers crashed to 14, apparently because of a deadly new disease called canine parvovirus that had ravaged domestic dogs on the mainland and may have reached the island on hikers' boots. And for more than a decade, even after all traces of the virus had disappeared, Peterson watched the population stagger along at a dozen or so animals and grow top-heavy with old wolves that had little success at replacing themselves.

By 1993, just three females survived, and only one of them had ever successfully raised pups. Wildlife biologists who followed the serial drama through Peterson's annual reports expressed fear that inbreeding had caused the isolated population to stagnate, as had happened with cheetahs in Africa.

Peterson demurred, suggesting that food or even bad luck might be the limiting factor. Whatever the reason, the predator-prey relationship was decidedly out of sync by the winter of 1995, when the moose population stood at 2,400 against 15 wolves.

"It was a matter of time until something broke," the scientist says, "and it broke in a big way." Everything turned against the moose at once in the winter of 1996, one of the severest on record. The temperature at the Isle Royale camp plunged to 43 degrees below zero Fahrenheit, the all-time low. Moose struggled through three feet of snow to find what little winter browse was left. The herd was infested with blood-engorging winter ticks that can cause serious hair loss and weaken even a big bull—but do not affect wolves.

Meanwhile, the wolf population had weathered a long crisis without human intervention (which would be counter to Park Service policy) and had climbed back up to 22. There were pups in all three territorial packs for the first time in nine years, and the predators were not hampered by the deep snow. They responded by hunting in larger packs, tripling the number of moose killed per day compared to normal, less snowy years.

After wrapping up his 1996 fieldwork at the end of February, Peterson reported that Isle Royale moose numbers had been cut in half, to 1,200. He described starving moose falling into Lake Superior when they leaned over steep cliffs to reach "the last tidbit" of browse. But the spectacular crash wasn't over. Spring arrived late and heavy mortality continued into June. "The length of winter was costly for calves and older, weaker moose," he says. "But a surprising number of young adults also perished." By the following winter, only 500 moose were left on the island, and the wolves, now numbering 24, were working hard to find food. "There were only a few calves for them to eat," Peterson reported at the time. "They even dug up the carcasses of dead moose and ate their sun-dried hides. I'd never seen that before."

Even so, Peterson expected the wolves to increase by the 1998 winter survey and was stunned to find that high mortality among both adults and pups had cut their number back to 14. "I didn't appreciate the severity of the food-shortage problem," he says today. The good news is that the population quickly bounced back, and the catalyst this time was an unusually hot and dry summer on an island usually swept by cool breezes or hidden in banks of moisture-laden fog.

"Moose don't perspire," Peterson explains, "and hot weather stresses them to the point where they have a hard time putting on enough fat to make it through the coming winter. Their diminished vigor makes them easier prey for wolves." Last winter he counted 850 moose in a herd that is slowly recovering, along with 29 wolves. And he was surprised to discover a realignment of wolf pack territories in response to changes in moose distribution. "Where we used to have three packs dividing the island, now there are only two."

In a few weeks, Peterson will be back in the air over wintery Isle Royale, flying at 500 feet for close-up views—through a 12-power, gyro-stabilized lens—of animals long accustomed to the ski plane's presence. He's reluctant to predict what he will find this time since "I'm usually wrong." But he adds that unless moose numbers are kept depressed for another decade, balsam fir will be a memory on the southwestern half of the island, where there is good soil and strong competition for growing space from northern hardwood trees.

Asked if he thought about passing the Isle Royale research torch to one of his graduate students, as Durward Allen did, the 51-year-old ecologist replies: "Not just yet. This is the last thing I would choose to give up. Friends tell me I'll probably die out there."

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