Bison in Grand Canyon

Bison grazing the North Rim of the Grand Canyon. 

To a park ranger, there must be days when he or she dreams of just letting the Grand Canyon be left alone.

Instead, there are overheated tourists to rescue, rafters on the Colorado needing help, and overflight pilots to keep from swooping too low. Nervous backcountry hikers are abusing their locator beacons and some are even launching drones in the park.

And up on the North Rim, there’s a herd of bison defying attempts to manage it.

The last challenge is a longstanding one – the bison were on the land even before the Park Service was established. They are wild but not pure bison, having been bred with cattle a century ago. And they are trampling meadows and watering holes as their numbers grow.

But they are also an iconic symbol of the West and, indeed, the entire Park Service – the bison is on its logo. Removing them entirely from the national park is not only impractical but out of the question politically.

Everyone does agree that 600 animals are too many – the carrying capacity of their preferred range in House Rock Valley outside the park is only about 100 animals. The Park Service is willing to settle for 200 bison that may or may not migrate into and out of the park, and for the first time they have proposed shooting some animals during controlled hunts inside the park over the next three to five years. Others would be captured, removed and delivered to the state, tribes or other entities.

Some conservationists, pointing to the example of Yellowstone, suggest reintroducing wolves to the North Rim. If humans are to cull the herd, they say, it should be done only by “non-lethal” means. But wolfpacks killing calves and weaker animals for food are OK.

From the standpoint of natural balance, there’s a certain logic to that plan. But wolves alone might not get the job done – the bison herd could grow to 800 in three years and as many as 1,500 in a decade. We’re no biologists, but with Senestech right here in Flagstaff pioneering animal contraceptives as a way to control pests, we wonder if science might be called on to help solve a problem that has defied wildlife managers.

Another scientific advancement – drones – might also help in ways that haven’t been tried yet. The bison retreat deeper into the forest the more they are hunted, so drones would seem a less intrusive and more cost-effective way of keeping track of them. And if those same drones dropped packets of food laced with contraceptives, a self-contained population like the North Rim herd couldn’t help but shrink.

For now, though, the challenge appears to be how to keep the animals who survive any means of culling from returning to and remaining in the park. Bison have shown through their behavior that they know the park to be a safe haven. Should the rules against hunting be waived more frequently so that the animals don’t become so complacent? And what if House Rock Valley were to become a hunt-free zone, instead?

It would be hard to argue that amid the millions of acres on the North Rim and the Arizona Strip, a herd of wild bison can’t be accommodated. But park rules might have to be bent, conservation principles rethought and modern science put to the test. The bison, unlike the Grand Canyon, aren’t going to withstand the forces of what we call “progress” without either an absolute sanctuary or some human help. The Park Service has made a good start and we urge various parties to let it take the lead in working through all of the thorny challenges that species preservation in modern times entails.

The National Park Service is now accepting public comment on its initial environmental assessment related to the reduction of the bison herd on Grand Canyon's North Rim. The 30-day comment period ends June 7.

To view the assessment or submit comments, visit


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