Friday could mark the last day this season of bison hazing operations in Yellowstone National Park, although controversy over the hazing likely will linger much longer.

The operations are being conducted under the terms of a 9-year-old agreement that included preparation of an environmental impact statement. Nevertheless, is the National Park Service adhering to its guiding mission of preserving natural resources unimpaired by participating in a project that has led to injured bison and which tries to overcome the animals' migratory instincts?

The hazing is authorized under the Interagency Bison Management Plan that federal, state and local authorities hashed out back in 2000. Under that plan, brokered by the state of Montana, the National Park Service, the U.S. Forest Service, and the U.S. Agriculture Department's Animal and Plant Health Inspection Service, the goal was to come up with a way to prevent Yellowstone bison from spreading brucellosis to cattle beyond the park's borders. (There has, however, been no documented case of such a transmission, although there have been suspected transmissions from elk to livestock.)

That agreement hasn't been overly successful over its life. It was about a year ago when the federal Government Accountability Office said the state and federal governments had exhibited a poor record in their efforts to battle brucellosis. Specifically, the GAO noted that the Interagency Bison Management Plan had been a failure on numerous fronts and the involved agencies needed to develop a better solution.

The GAO report not only said the various agencies were at times dysfunctional, but also noted that the management plan was just that -- a management plan, not an eradication plan. "Multiple recent suspected transmissions of brucellosis from elk to cattle in the area have highlighted the importance of addressing this disease in its broader wildlife and ecological context, and doing so could have significant implications for the future management of Yellowstone bison," the report said.

Which brings us to this year's hazing, which sounds vaguely reminiscent of operations on Yellowstone's Northern Range back in the early 1960s to manage the park's burgeoning elk herd. Those efforts involved helicopters herding thousands of elk to their deaths. The story caught wind nationally, in part because of the fact that some elk broke legs trying to flee the helicopters and had to be killed on the ground where they lay thrashing in pain.

"One wounded cow was squealing and the butchers, who were unarmed, had to dispatch the pitiful animal with a hand-ax," read one account in Sports Afield. John Varley, now retired from his job as Yellowstone's chief of research, in 1997 vividly recalled the images that fanned public outrage.

"It had a real Vietnam look to it," he said at the time. "A lot of helicopters, a lot of rifles. After that started getting televised, I think every school in America wrote their congressmen."

Today's bison hazing is not anywhere close to being on the same scale, but the scenes still are troubling in that they are coming from inside the world's first national park, a park that presumably is a sanctuary for wildlife. Helicopters from the state of Montana at times are flying as low as 20 feet or so above ground inside the park to push herds of bison ranging in size from 200-250 animals as much as a dozen miles into the park's interior, according to Yellowstone spokesman Al Nash.

The bison, young and old, are forced to cross the Madison River, which is running high with snow melt.

The park spokesman maintains nothing improper is being done.

“As we have for several years, there is nothing new about our hazing operations on the west side of the park this year. It is in conjunction with our interagency partners under the Interagency Bison Management Plan," Mr. Nash said Friday morning. "Nothing different than we’ve done for several years. Moving bison from outside to inside. And moving them to locations inside the park where we believe that there is good forage that will keep them within the park boundaries.”

He would not, however, respond specifically to whether these operations conflict with the Park Service's mission under the National Park Service Organic Act.

“This is part of our agreement under the 2000 EIS with our interagency partners, whose goals are to conserve a viable wild bison population, and mitigate the risks for transmission of brucellosis,” replied Mr. Nash. "There is limited tolerance for bison outside the park. We entered into this agreement several years ago after years of acrimony and legal challenges.”

In trying to see the hazing end, the Buffalo Field Campaign focuses on vividly portraying the ground operations. In a release Thursday the group's executive director, Dan Brister, says Yellowstone officials are allowing "agents on horseback and the (Montana Department of Livestock's) helicopter to force wild bison off the ground they choose to be on, right in front of the eyes of park visitors."

"Buffalo have been run for miles without rest, water, or time to nurse; chased across swollen rivers, through thick mud flats, fallen timber, paved roads, and dusty trails," he adds. In some cases, calves have suffered broken legs.

Mr. Nash had no information of calves being injured, though he did say a cow with a broken leg was spotted Thursday on U.S. Forest Service land outside the park in Montana. But he added that bison break their legs under natural conditions, as well.

“I ... see animals in the Lamar Valley with broken legs. I saw a couple there a couple of weeks ago, bison. We haven’t done any hazing in the Lamar Valley," he said.

Back at the Buffalo Field Campaign, officials see nothing normal about the hazing operations on the park's west side.

"It is a centuries-old, cattle industry driven war against wildlife," they say.