Minnesota trappers have been twice as successful killing wolves as early-season wolf hunters, according to preliminary harvest results from the state's inaugural seasons.

So far, about 8.5 percent of licensed trappers have bagged wolves, compared to 4 percent of hunters during the early wolf season. And in the late wolf season -- which began Nov. 24 and runs until Jan. 31 -- about 69 percent of the wolves killed so far have been taken by trappers, though they are outnumbered 2-to-1 by hunters.

"We've known that trapping is the most effective method to take wolves, so it's not surprising," said Ed Boggess, Department of Natural Resources Fish and Wildlife Division director. "Trappers can place multiple sets, and the traps are out there 24 hours a day. Hunters have to be there when the wolf is there."

Meanwhile, late-season wolf hunters are having a 2 percent success rate -- half that of early-season wolf hunters. Still, Minnesota wolf hunters have done better than their counterparts in Montana and Idaho, where wolf hunt success rates have been around 1 percent.

DNR officials have been collecting samples from harvested wolves and have been surveying successful hunters and trappers. Much information has yet to be analyzed, and there's still almost six weeks left in the season, but here's what they have found so far:

• About 85 percent of the 147 wolves killed during the early wolf season -- which ran concurrently with the firearms deer season -- were taken incidentally while the hunters were deer hunting. The remaining 15 percent were killed by those who specifically targeted wolves, sometimes with bait or by using calls.

• Fifty-four percent of the wolves killed were males.

• Fifty-four percent were killed on public land; 46 percent were taken on private land.

• About 10 percent of the wolves had some mange -- a parasite that burrows under the skin, causing hair loss. "On some of those wolves, almost half of them were bare skin," said Dan Stark, DNR wolf specialist. "Those animals likely wouldn't make it through a severe winter. They would die from exposure."

• Three radio-collared research wolves have been killed.

As of last week, hunters and trappers had killed about 276 wolves over both seasons; the quota is 400. But for the year, about 560 wolves have been killed in Minnesota, including 267 taken by federal and state trappers in response to livestock depredations, and 16 killed by citizens protecting livestock or pets.

The kill represents about 19 percent of the estimated 3,000-wolf winter population.

"That would have no influence on the [overall] population," Stark said. He said mortality would have to reach 30 percent to impact the wolf population, "and that has to happen over a number of years." But opponents of the controversial hunt say the state shouldn't allow a wolf hunting and trapping season at all, and that the killing could disrupt packs and cause other problems.

Stark says the surviving female wolves will reproduce next spring, and he expects their offspring to replace those killed in 2012, leaving the wolf population essentially unchanged.

Successful hunters and trappers are required to bring the wolf carcasses to the DNR so samples can be taken, and hunters and trappers are being surveyed so the DNR knows where each wolf was killed. A tooth is taken from each wolf to determine its age, and reproductive tracts are removed from females so officials can determine the size of litters. Officials also are taking liver and kidney samples to screen for heavy metals such as lead and mercury.

None of that lab work has been done yet.

The wolves won't be tested for Lyme disease, rabies or other such illnesses. "We would need to take blood samples to do that, and you can't get whole blood from a dead animal," Stark said.

He said tissue samples also are being taken and stored in case researchers want to do future genetic research.

Hunters and trappers also will be surveyed after the season. "We don't know how many people who bought licenses actually hunted or trapped," Stark said. Trappers also will be asked if they used foot-hold traps or snares.

All of the information -- combined with a wolf population survey already started -- will be used to assess the first seasons ever and determine if any changes will be made next year. The population survey is the first since 2008. Stark said all the information should be ready by mid- to late-summer so officials have time to incorporate the results into next year's wolf hunting and trapping seasons. Lawsuits challenging the hunts could alter those plans.

Stark said officials can't explain the higher success rates hunters and trappers are having in Minnesota compared to western states. Could it be because the wolf population here is higher than believed?

"I don't think so," Stark said. "I think our population estimate is pretty well supported and accepted methodology. The population could be slightly above where we were in 2008, but not significantly higher."