---
title: "Oklahoma prairie herd that began with 300 donated bison in 1993 now tops 2,000 animals"
url: https://badiyaa.com/tallgrass-prairie-preserve-bison-herd-oklahoma/
published: 2026-10-19T05:47:00+01:00
modified: 2026-10-19T08:09:31+01:00
section: Pets & Animals
publisher: Badiyaa
---

# Oklahoma prairie herd that began with 300 donated bison in 1993 now tops 2,000 animals

The founding animals came from Kenneth and Dianna Adams's Ken-Ada Ranch. The herd now swings from about 2,100 in winter to 2,700 in summer, and is out of view until November 20.

Thirty-three years ago this weekend, on October 18, 1993, The Nature Conservancy opened the gates on 300 bison at its preserve near Pawhuska, in Osage County, Oklahoma. That herd now winters at about 2,100 animals and climbs to roughly 2,700 each summer once the spring calves arrive, according to the Conservancy’s own herd figures. The story has been circulating widely again this week; the record behind it holds up, with one correction about the donor and a timely warning for anyone planning a trip.

## Who gave the bison

Viral posts describe the donor as “a rancher.” That is close, but it leaves out the names. The Conservancy says the founding animals came from the Ken-Ada Ranch, north of Bartlesville, owned by Kenneth and Dianna Adams, and that the herd carries the name of their daughter: it is officially the Christina Adams Bison Herd. Kenneth Adams is described in the preserve’s encyclopedia entry as an Oklahoma oilman, so “ranch owner” is the more accurate label.

The land itself had been bought four years earlier. In 1989 the Conservancy acquired most of the old Chapman-Barnard ranch, and in 2015 the site was renamed the Joseph H. Williams Tallgrass Prairie Preserve after the founder of the group’s Oklahoma chapter, who died in 2023.

## From 300 to about 2,100: the numbers, step by step

- **1905:** a national count found 835 wild bison and 256 in captivity across the country, the Conservancy notes.

- **1993:** 300 animals released on the Osage County prairie.

- **2000:** the herd had reached about 1,200.

- **2023:** at the 30th-anniversary event, around 1,800 bison were reported on the land.

- **Now:** about 2,100 bison through the winter and about 2,700 at the summer peak, with 600 to 700 calves on the ground by mid-May.

Work it through and the winter herd is seven times its founding size (2,100 divided by 300). The total does not run away, because people do the job wolves and grizzlies once did. Every fall the animals are rounded up for vaccinations and weight checks, and some are sold: bulls at six to seven years old, before they become more aggressive, and cows at 10 to 12. Each animal wears an ear-tag transponder that records its sex, age, weight and pregnancy status.

## How it compares with Yellowstone

Yellowstone National Park holds the best-known herd in the country, and the comparison is useful. The park’s 2025 estimate put its bison at nearly 5,300, and in recent years the count has swung between 3,500 and almost 6,000. Yellowstone fell to about two dozen animals by 1902, when poaching nearly wiped out its herd, and it remains the only place in the lower 48 states where bison have roamed continuously since prehistoric times.

On those figures, the Oklahoma winter herd of about 2,100 is close to 40 percent of Yellowstone’s (2,100 against 5,300), on a single privately run preserve of 39,650 acres. The difference is that Yellowstone’s animals migrate as much as 70 miles between seasons, while the Pawhuska herd lives inside fences on more than 30,000 acres and gets salt with trace minerals but no extra feed.

## Why the grass needs them

Tallgrass prairie once covered parts of 14 states, from Texas to Minnesota. Less than 4 percent of it survives, mostly because it was plowed for crops or built over. The Osage preserve escaped the plow largely because its rocky limestone ground made cultivation hard. “This has always been tallgrass prairie, so it’s never been plowed,” preserve manager Tony Brown said in a 2023 interview. He credited bison wallows and trampling with creating small habitats for other species.

Fire does the other half of the work. Under a “patch-burn” approach, about one-third of the prairie is burned each year, and bison follow the fresh green growth. The preserve lists more than 700 plant species, 300 birds and 80 mammals, including greater prairie-chickens and the endangered American burying beetle.

## If you plan to visit

The preserve is open from dawn to dusk every day and charges no admission. Most visitors drive the 15-mile bison loop, and the Conservancy asks people to stay in their vehicles around the animals, which can run at up to 35 miles per hour. Dogs, camping and off-road driving are not allowed. Three short self-guided trails start near the old ranch headquarters, now a visitor center staffed by volunteer docents on scheduled days.

One warning for anyone inspired by this week’s posts: it is roundup season. The Conservancy says the herd went out of sight from the road on October 1, and it expects to finish wellness checks and return the bison to the open prairie by November 20.

## Further reading

- [Wikipedia: Tallgrass Prairie Preserve](https://en.wikipedia.org/wiki/Tallgrass_Prairie_Preserve)

- [National Park Service: Bison Ecology, Yellowstone](https://www.nps.gov/yell/learn/nature/bison.htm)

*Image: Photog, CC BY 3.0 via Wikimedia Commons*

*This article was produced with AI assistance and reviewed by our Editorial Desk. [How we work](https://badiyaa.com/editorial-policy/).*