Minnesota's wolf population is robust enough to have another wolf hunting and trapping season this fall, despite a 24 percent decline since canis lupis was last surveyed in 2008, state officials said Tuesday.

Although opponents of the wolf hunt said the population drop is evidence that wolves are in peril and shouldn't be hunted or trapped for sport, state officials said the population, estimated at 2,211, is healthy and the largest in the lower forty-eight states.

"Minnesota's wolf population is fully recovered from its once threatened status,'' said Dan Stark, Department of Natural Resources (DNR)large carnivore specialist. He said the DNR will offer a wolf season next fall, although the quota will be reduced from the 400 allowed in last year's inaugural season.

The wolf survey has been highly anticipated by both supporters and opponents of th hunt, and state officials said it shows that Minnesota wolves, like all wildlife populations, are constantly in flux.

The survey was done in midwinter before wolf pups were born. Since then, Stark estimated about 2,600 pups have been born, and about 50 percent of those normally will survive at least until fall. That means the current wolf population this summer likely exceeds 3,000.

But hunt opponents note that the DNR's population estimate has a margin of error of about 500, meaning the population could range from a high of 2,641 to a low of 1,652 — very close to the state's minimum goal of 1,600.

"We see this as a significant decline," said Howard Goldman, Minnesota state director of the Humane Society of the United States. "The department should protect the wolf and close the season."

Said Collette Adkins Giese, a Minneapolis attorney with the Center for Biological Diversity, which unsuccessfully sued to stop the hunt: "Sport hunting and trapping strains a Minnesota wolf population that's already under dangerous pressure from a declining prey population, disease, depredation control and illegal killing."

Stark and John Erb, a DNR research biologist who worked on the study, said the population drop over the past five years likely was from several factors, including a 25 percent decline in whitetail deer, wolves' primary food source, as well as a very mild winter with little snow last year, which made it difficult for wolves to catch deer. The killing of 413 wolves by hunters, trappers and almost another 300 by officials responding to livestock depredations also contributed to the decline.

The DNR in recent years deliberately reduced the deer herd in some areas with liberal hunting regulations, and now is trying to boost deer numbers in those regions.

"Wolf populations are resilient and highly productive," said Stark. "We're now making adjustments to increase deer numbers, and will likely see a positive response from wolves."

The DNR wolf survey showed a 13 percent increase in average wolf pack territory size to about 62 square miles, likely caused because wolves had to travel farther to find deer.

The survey also showed 438 wolf packs in the state, but the average number of wolves-per-pack fell from 4.9 to 4.3, which likely was due to the reduced prey availability and the killing of wolves by hunters and trappers.

The survey is conducted in winter when wolves are easier to spot and also when their population is at its lowest point of the year. In 2008, the survey estimated a population of 2,921 — a number that was criticized by some as too low and by others as too high. The results of this year's survey seems to support that estimate.

"I think our estimates have been pretty reliable," said Erb.

Officials said the DNR will more closely monitor pack and territory sizes in the next few years, and will use more frequent radio collaring of wolf packs to determine effects of the wolf season harvest. Details of this fall's wolf season are expected to be released later this month. Last year, hunters and trappers killed 413 wolves, or about 14 percent of the winter population of 2,900. If that percentage is used by the DNR this fall, the quota would be around 300 wolves.

The Minnesota Court of Appeals in May threw out a challenge to the wolf season by the Center for Biological Diversity and Howling for Wolves, saying they had no legal standing to sue because they couldn't show the DNR had caused injury. The judges noted that it was the Legislature, not the DNR, that established a season on wolves.

Meanwhile, a federal suit by four wildlife advocacy groups challenging the U.S. Fish and Wildlife Service's decision to remove wolves from the federal endangered species list has yet to be heard.

The DNR's survey is available at www.mndnr.gov/wolves.

Doug Smith • 612-673-7667