The elk herd that has become one of the hottest flashpoints in Montana's wolf wars showed a marked decline last year, http://www.nps.gov/yell/parknews/11005.htm">according to numbers released Wednesday by Yellowstone National Park.

The elk herd that lives along the park's northern border declined by 24 percent between 2009 and 2010, according to an aerial count conducted in December.

State and federal biologists attribute the decline to predators, drought and hunters.

But complicating matters is the fact that wolf and grizzly bear numbers have also declined in recent years, as has the amount of hunting the Montana Department of Fish, Wildlife and Parks allows in the area.

"This is odd," said Doug Smith, a Yellowstone biologist. "For five or six years, we had a fluctuation of 5 to 10 percent. This year's count was outside that fluctuation. There's a question mark. Why?"

Karen Loveless, an FWP biologist who worked on the count, agreed that the drop was surprising.

"Wolves were down. The (elk) hunting harvest has been cut way back - we're really just harvesting bulls out of there," she said. "I don't have a great explanation why it decreased this year and last year it did not."

Smith noted that environmental factors combined with predators and hunters could be the answer.

But he also suggested that the heavy snow this winter may have clouded biologists' count, producing artificially low numbers.

The herd is closely watched by the public because of its interaction with wolves. Both sides of the debate over wolf reintroduction have used its numbers as evidence of either the positive or devastating affects of wolves.

In 1995, the year wolves were reintroduced to the Greater Yellowstone Ecosystem, the northern Yellowstone elk herd numbered 16,791.

In 2009, biologists counted 6,070 elk in the herd.

Last month, biologists counted 4,635 elk.

All told, the elk population has declined by 70 percent in the 16 years since wolf reintroduction.

Wolf advocates argue the herd was grossly overpopulated and damaging the ecosystem around it before wolves were brought back. But the decline in population has angered many hunters and outfitters who enjoyed the long hunting seasons around Gardiner and Cooke City that used to run into January.

But wolves are not the only factor in the size of the herd, Smith said.

"It's incorrect to say (wolves) are the only reason for it," he said, pointing out that the wolf population has declined in the area recently, too, from 94 to 37, likely in response to the lower elk numbers.

"The other reason that's harder to put our finger on is that since wolves were recovered, we went through a 10-year drought," Smith said.

Drought conditions during the early 2000s appear to have impacted the nutrition and abundance of forage, and may have lowered reproduction rates in some elk, the park said in a press release that accompanied the new numbers.

FWP hunting quotas have been set low enough to not affect the elk population north of the park, Loveless said. Only 30 antlerless elk were allowed to be hunted last year.

As for the famed Gardiner Late Hunt, the number of permits issued for the antlerless elk declined from 1,102 in 2005 to just 100 permits during the 2006-2010 seasons. The late-season hunt was eliminated altogether this year.

The largest decline of elk this year was seen inside the park, Loveless said. Still, the number of northern-herd elk in Montana was below the state's objective of the area of 3,000 to 5,000. There were 2,236 elk counted in the Montana portion of the herd's range.

Daniel Person can be reached at dperson@dailychronicle.com or 582-2665.