A calf and her mother graze on the 1,100 acre Windmill Pasture at the Tallgrass Prairie National Preserve near Strong City. 22 bison now populate the preserve. In 2009, 13 of them were brought from Wind Cave National Park site in the Black Hills region of South Dakota.

STRONG CITY ? You can tell there is some tension.

The tail is the first sign that gives it away. It is sticking straight up. Then there is the eye, planted in the side of a wide, steady head. It is not staring directly at you, but there is no doubt it sees you as plain as the sky is clear on this beautiful early fall day in the Flint Hills.

As he pleases, this 1,400-pound bison — his back hump stands nearly as tall as the cab of a pickup truck — turns and faces you. Horns that protrude above a tuft of woolly hair are pointed at you. The big bull starts to walk at his own deliberate pace toward the group of visitors standing nearby.

There’s a general rule about a bison on the move: It’s best if you move a bit faster than the bison. So everybody scurries and shuts the truck doors tightly behind them.

That leads to another saying about these animals: Bison have no boss. At least none with two legs.

“That’s pretty obvious,” says cowboy Gene Matile, the ranch manager for this herd of bison — or buffalo, if you want to be informal. “He made all of us move.”

You would expect that. Ruling the range is in a bison’s DNA. But what you would not expect is that here — atop a hill in a pasture at the Tallgrass Prairie National Preserve just outside of Strong City — is where you would stumble upon a family dispute.

You have, though. The only familial element this herd of circling buffalo is missing is a dining room table. Employees here at the Tallgrass preserve say it has been interesting to watch how tightly the bison stick together on this 1,100-acre pasture about 100 miles southwest of Lawrence. They’ve watched with admiration how a bull buffalo will defend any calf in the herd, regardless of who sired it.

But the herd has at least one other family trait. Sometimes there are hard feelings. Sometimes they get mad at each other.

In this Chase County locale, where horizons are free and deep, you can see big bluestem waving in the wind, two deer on a faraway ridge, but most noticeably — about three-quarters of a mile away — a lone bull buffalo.

Perhaps sulking, perhaps plotting, he is now on the move. It looks like a family reunion is in the offing.

“Oh yeah,” says Paula Matile, Gene’s wife and a conservationist with The Nature Conservancy that brought this herd from South Dakota three years ago. “There’s definitely a family dynamic here.”

And you thought your family was wild.

• • •

What Kristen Hase, chief of natural resources for the preserve, can’t understand is how a 1,000-pound animal seemingly can hide on a wide-open prairie.

“It is kind of amazing how a big animal can disappear out here,” Hase says as she maneuvers a government-issued Ford Explorer across the rocky terrain known as Windmill Pasture.

You can try to gauge the wind and make a good guess where the buffalo will be. Bison, it is thought, like to walk into the wind. But that works about as often as a flipped coin lands on tails, so usually you will find the buffalo when you find them.

Slowly, visitors to the preserve are beginning to find the animals. It has been three years since leaders with the nonprofit Nature Conservancy and National Park Service went to Wind Cave National Park in South Dakota to get young bison from the herd long credited with helping stave off extinction of the species. The Journal-World in 2009 chronicled the trip from South Dakota to the Tallgrass Prairie National Preserve, which is the former 11,000-acre Z-Bar Ranch.

Park officials left South Dakota with 13 bison ranging in size from 350 to 750 pounds. Now, the herd has grown to 22. One of the original herd members died, and two new ones have been purchased, but the rest have come from mothers having calves. Come summer, another four or five could be added to the herd through the birthing process.

Eventually, the herd is expected to grow to between 75 and 100 head. But that will take time. What has not taken long is for the buffalo to make this piece of tallgrass prairie home.

“It has been great,” says Paula Matile, a conservation specialist for the Kansas wing of The Nature Conservancy. “We wanted to preserve the idea of the wandering herd on the prairie, and that is what has happened.”

Leaders of the preserve work hard to keep the animals as natural as possible. Mainly, that means letting them be. Gene Matile, a bison caretaker at the Tallgrass Prairie National Preserve, and his 5-year-old daughter drive the pickup into the pasture about once a week to count the herd, and occasionally they open the doors on a portable feeder to attract the buffalo to the truck.

Park leaders want the animals familiar with the pickup truck because they plan to use the truck to lure the herd into a set of corrals when the park holds its first roundup, which may happen next year. Seven-foot-tall, steel-paneled corrals are still in the process of being built.

In South Dakota, Wind Cave officials used a helicopter to gather the herd, but that’s not the plan here.

“I told them I wasn’t driving the helicopter,” Gene says.

When asked what he thinks that first roundup will be like, he responds in the understated manner that typifies this place.

“Interesting,” he says. “Pretty interesting.”

Visitors already are finding it all to be pretty interesting. Most, however, stumble upon the national preserve without ever knowing the park has buffalo. Word of the bison herd is spreading slowly, says Jeff Rundell, a park guide.

But when visitors learn of it, they become excited. The park from late April to late October offers bus tours of the pasture two times a day, every day — although funding concerns always make the future of that program precarious.

The park also lets people hike on its 40 miles of trails whenever they please: Nothing but a few blades of switchgrass between you and wild animals. Hase has put up signs warning that bison are dangerous animals, and she hopes you read them. But at its core, this is still a place where you’re free to get yourself into as much trouble as you think you can get out of.

“Hopefully people will be smart about it,” Hase says. “Unlike Yellowstone, we don’t have any trees here, so good luck because bison are unpredictable, and they’re fast.”

That’s why Rundell says the best way to see the herd is in his bus. But however you do it, he says it is worth the effort.

“My favorite sight is when the buffalo are against the backdrop of nothing but the Flint Hills,” Rundell says. “No roads. No buildings. It kind of stirs you.”

• • •

There have been no second thoughts from the lone buffalo. He’s still walking up the northern slope.

His clan has noticed. They now start to congregate around the parked pickups, and you see buffalo like few rarely do — the matted fur, the cobweb of cockleburs under their chins.

“Don’t you want to just brush them?” Paula says.

“I’ll get you a brush,” Gene says, “but you had better hope it has a long handle.”

There are some things, though, not even a brush could fix: nicks, scrapes, gouges.

Everybody turns to Gene — who also oversees more than 2,000 head of cattle that graze on other pastures of the preserve — assuming he would have an explanation for how the wounds got there.

“I don’t know,” he shrugs. “I guess they got mad at each other.”

As the lone bull gets a little closer, it becomes clear he may know the answer better than most. Part of his tail is missing.

“He doesn’t look as bright as the others,” Gene says. “But I’m betting he got the poop whooped out of him not too long ago.”

As the lone bull reaches the herd, two bulls step out from the pack to meet him: One in front of the newcomer and one behind.

The tension is back.

“I think they are about to show him the stuff,” Hase says.

But horns don’t lock. The new bull stays on the outside edge of the herd, but he’s no longer alone. The hatchet has been buried — for now.

With that, the biggest bull turns his attention back to the pickup trucks: staring like a brick wall with eyes.

Yeah, he’s the boss. Every family has got one.