Bison herd at Nachusa Grasslands.
Nachusa Grasslands Bison herd © Charles Larry

Stories in Illinois

Nachusa Grasslands Bison FAQs

Do you have questions about Nachusa's bison herd? We've got answers!

Why did you bring bison back to Nachusa?
Re-establishing bison was the natural next step in the restoration process at Nachusa Grasslands. Their grazing behavior and the effects they have on the prairie with their hooves and horns naturally promotes biodiversity and help a wide range of wild flowers, plants, insects and amphibians to flourish.

How many are there?
Nachusa's herd is comprised of 110 animals, with roughly 40 calves arriving each spring, bringing the herd total to 150.

Where did they come from?

The bison came from Wind Cave National Park in South Dakota and other TNC herds founded with bison from Wind Cave. Unlike most other American bison, animals from the Wind Cave herd have no history of cross-breeding with cattle and they are genetically diverse.

How are Nachusa’s bison different from other herds?

While there are other bison herds present in Illinois, they typically are on small farms and raised for meat production similar to cattle. The Nachusa herd is the first conservation herd in the state: their primary job is to help maintain the health of the prairie at Nachusa.

Has TNC done this before?

TNC has more than 40 years of experience reintroducing bison throughout the Great Plains of Iowa, Kansas, Missouri, North Dakota, South Dakota, Oklahoma, Colorado, and Nebraska.

How is the bison herd cared for?

Each fall, the bison are rounded up for one day for health checks and annual vaccinations by a veterinarian to keep the herd healthy. This is also the time when some animals are sorted off from the herd to go to another ranch or preserve to improve the genetic health of the species. Additionally, each year a sale takes place to maintain Nachusa’s herd size. Based on our herd structure and demographics, we may sell as many as 40 animals, primarily yearlings and older bulls.

Will I be able to see the bison?

Stop by our Visitor Center and visit the overlook that provides a view of the prairie and the herd (depending on where they are grazing). You can also see the bison by bringing your binoculars to view them from one of the public roads. Please note: the bison roam across 1,500 acres of rolling landscape and may not be visible at times. No hiking is permitted inside the fenced bison unit. The other units of the preserve are open dawn to dusk for hiking.

When can I see calves?
Bison calves are typically born in April, May and June. Cows will find an area with good cover and give birth unaided. Their young are 50 pounds at birth, can keep up with the herd shortly after being born, and are weaned in about one year. If you visit Nachusa during this time period, you may be able to see calves traveling with the herd, but please remember: Unless accompanied by a trained volunteer or staff member, no one can enter the bison unit on foot or drive into the bison unit. We also ask that you stay 100 yards from the bison at all times, even when separated by a fence. Cows are extremely protective and will defend their calves if they feel threatened.

Can I still come to Nachusa?

Visitors are welcome and encouraged to visit Nachusa! The preserve is open from dawn until dusk. Our Visitor Center will help you enjoy your trip and learn more about the preserve.  Please note: Hiking is not permitted in the bison unit.