Minnesota’s first intensive wolf population survey in five years will end soon, when the snow disappears in the north woods. The results, which won’t be known until at least late spring, will give wildlife officials and residents a fresh estimate on how many wolves roam the state.
But whether the population is up, down or unchanged won’t likely damper the controversy over whether canis lupus should be hunted and trapped.
That simmering dispute was apparent last week at an overflowing State Capitol hearing room where legislators heard testimony on a bill to place a five-year moratorium on wolf hunting.
John Gilbertson, a farmer from the Bemidji area who said he has lost numerous livestock to wolves over the years, said he has a different view from city folk who long to hear the howl of a wolf.
“If I’m lying in my bed at home and my wife and I hear a wolf howl, it means we’d better hit the floor running because he’s probably after one of the livestock in the yard,” he said.
Howard Goldman, state director of the Humane Society of the United States, was among those arguing to end the wolf hunt.
“There’s no biological reason to hunt them,” he said. “We don’t eat them. It’s just sport.”
John Erb, a Department of Natural Resources wildlife biologist who is coordinating this winter’s wolf survey, said those on both sides of the wolf issue likely will use the new wolf population estimates — no matter what they are — to argue their case. And though Minnesota’s wolf survey is the most comprehensive done anywhere, some still question the survey’s accuracy.
“Both sides are misusing the numbers,” Erb said. “It’s a social debate. Some people are against the killing of a wolf. Some people are OK with it, but are not against wolves. And other people want us to kill a lot of wolves; they don’t like them.”
The last survey, done in 2008, showed about 3,000 wolves. But people mistakenly seize on that number, forgetting it is the wintertime estimate when the population is at its lowest, Erb said.
This spring, when wolf pups are born, the population could nearly double. Many of those pups won’t survive, and other wolves will die during the year.
Still, the fall wolf population, before last year’s hunt began, could have been 4,200 or 4,300, Erb said. While the latest survey results won’t be ready until late spring or early summer, Erb said there are some indications the wolf range has expanded a bit and other indications the average territory size of wolf packs might be a bit larger.
There also are indications wolf pup production last spring might have been poor. Ultimately, Erb thinks the wolf population may not be much different from the last survey, which showed a winter population ranging from 2,900 to 3,500 — or about 3,000 wolves.
Though opponents of a wolf hunting season argue the state should have waited until after this year’s survey, so officials would have a current wolf population estimate, Erb said the DNR conducts two other surveys yearly that give an indication of the wolf population.
“We’re not operating in a vacuum,” he said.
One of those is a scent-post survey done each fall, where officials place scented discs along 400 routes around the state and then count the tracks from animals — including wolves — attracted to it. The other is a winter track survey, where employees drive designated routes after fresh snowfalls to count animal tracks, including wolves, bobcat, fox, fisher, marten, snowshoe hares and even weasels.
Both offer population indexes, which show trends. In recent years, both have shown high wolf numbers. Also, the DNR looks at detailed wolf depredation reports, which adds to the population information.
How wolves are counted
“You don’t just go out and count wolves one by one,” Erb said.
Instead, officials try to estimate the population using sightings, tracks and radio-telemetry data fed into formulas.
First, hundreds of employees with state, county and federal agencies, including the DNR, U.S. Forest Service, Fish and Wildlife Service and tribal bands, are asked to record wolf sightings, or wolf signs, when they are afield doing their regular jobs. The goal is to identify areas currently used by wolves, Erb said.
That information is combined with data from other track surveys and is entered into a database. The DNR and other researchers also have 40 to 50 wolf packs with radio collars that it monitors, helping estimate the number of packs and overall population.
The past two surveys showed an estimated 500 wolf packs, with an average pack size of about five. An average pack uses 40 square miles. Officials also must account for lone wolves not in packs, relying on previous studies.
“We use 15 percent,” Erb said. “So we add that to the population.”
The survey costs about $50,000. This year, the DNR also will look at the wolf harvest information — where wolves were killed by hunters and trappers. Eventually, all of this information will produce a population estimate, with a margin of error of perhaps 500 to 700 wolves.
“No survey is perfect, but I have confidence [in it],’’ Erb said.
Still, when the numbers come in, no one expects the heated wolf rhetoric to end, either at the State Capitol or in the courts. Four groups last month sued the U.S. Fish and Wildlife Service, seeking to put the predator back on the federal endangered species list less than a year after it was removed.