Last week it was time for the annual nitty-gritty of bison herd maintenance at the Nature Conservancy’s Tallgrass Prairie Preserve. It was time for weighing and shots and the inevitable decisions about which bison will be around for the next roundup, and which ones may be on the way to the great bison herd in the sky.


Katie Hawk, spokeswoman for the Nature Conservancy, drew attention to the artful skill with which the ranch hands working the annual roundup use their trucks to “dance” across the prairie and drive the bison into a holding pen just after first light. She also explained that with some 500-700 new bison born every year, it is necessary to cull the herd down to its overwintering size of some 2,100 animals. Most of the bulk sales go to meat producers.


That means, as the ranch hands say while working the line, some are “keepers” and others are “sellers.” This was the 25th annual bison roundup at the Tallgrass Priarie Preserve and current Preserve Director Bob Hamilton has seen them all —though not all as director.


“The thing that impresses me about is they’re so resilient,” Hamilton said, contemplating the issue for a few moments as he helped work the animals coming through the line Thursday morning. “They’re the ultimate low-maintenance type animal. They don’t really like to be messed with that much.”


Amen. The larger animals, particularly the bulls, gave the equipment designed to hold them for weighing as much as it could handle.


If they aren’t culled out earlier, a bull bison may live about six and a half years at Tallgrass. There are exceptions to that, Hamilton said, noting that one of the bulls in the herd last week was nine years old. Females can live some 10-14 years, he said.


The herd lives on about 24,000 acres of the roughly 40,000 acre preserve north of Pawhuska. Its grazing, along with fire, are key tools in the management of the land. The importance of that, lest anyone be allowed to forget, is that the John H. Williams Tallgrass Prairie Preserve is only the largest chunk of tallgrass prairie left on the planet.