Wolf population in Minnesota is shrinking
By JOSEPHINE MARCOTTY
Minneapolis-St. Paul Star Tribune
GRAND RAPIDS, Mich. – After flourishing for a quarter-century in the forests of northeast Minnesota, the timber wolf population in the state has peaked and may be shrinking.
That change in direction has surprised wildlife experts and defied earlier predictions that protection offered by the Endangered Species Act would allow the wolf to spread across the state.
State wildlife officials, who have tracked the growth of the wolf population for decades, intend to complete a new survey this summer that they expect will show little change since 1998. The results will raise questions about how much effort will be needed to handle the wolf in the future and whether it will ever find its way south.
Ever since it was placed on the endangered species list in 1974, the timber wolf has steadily expanded its range. Space is vitally important to the territorial animal. Each one occupies about 10 square miles of land, which means that, on average, a pack of six wolves lives in 60 square miles.
And the wolves don’t share territory. When a wolf encounters another that’s not from its pack, they fight, often to the death.
Wildlife biologists are now recognizing that, since the late 1990s, their growth has been thwarted by disease, parasites and a series of mild winters that has favored the white-tailed deer in the contest between predator and prey.
Some experts say all of that is nature’s way of controlling a population that has saturated all the suitable territory in the state. If they’re right, Minnesota may never have more than its current 2,000 to 2,500 wolves. Meanwhile, much smaller wolf populations in Wisconsin and Michigan continue to grow.
Not everyone agrees with that theory. If nature’s balancing act shifts in favor of the wolves, their population growth could force them south. Unlike Minnesota’s north woods, these new lands contain more farms with livestock, more people with pets and more potential conflicts.
David Mech, a wolf expert and founder of the International Wolf Center in Ely, Minn., believes the wolves’ move south is only a matter of time.
“The biggest food supply is just south and west of where they are now,” he said. “The wolves will get there sooner or later.”
There is agreement among wolf experts on at least one thing. “Wolves have continually surprised us,” said John Erb, a wildlife biologist with the Minnesota Department of Natural Resources.
Logging roads wind endlessly through the forests that surround Grand Rapids. In springtime, when the trees are an iridescent green, the muddy roads are pockmarked with the pointed hooves of deer. Mixed among them is an occasional paw print or scat pile left by a wolf.
This is in the Minnesota wolf range, a place where for 10 years state government researchers have traveled the roads to study the relationships among deer, wolves and weather.
Seven to eight wolf packs occupy the wooded study sites. Each year, researchers trap wolves and does and hang radio collars on them so they can track the fates of predators and prey through the seasons.
What they have found is that the connections are surprisingly intricate.
Harsh winters with deep snow shift the balance of survival in favor of the wolf. Deer, weakened by a winter diet made even more sparse by heavy snow cover, are easier for wolves to catch as they flounder through deep drifts.
They are especially vulnerable after midwinter thaws. The temporary warmth softens the snow on the surface, and then it freezes to a smooth, hard surface. Wolves, with their wide, splayed feet, can run on top of the crust. Deer, with their pointed hooves, break through, said Glenn DelGiudice, the wildlife biologist who is running the study.
“The deer’s nutritional condition is worsening; their endurance is diminishing. And wolves have the advantage,” he said.
But in milder winters with less snow, the reverse is true. Deer have better food supplies – and they can run away. Wolves, which have few other food choices in winter, starve.