Every October on the Tall Grass Prairie Preserve (TGP) scientists conduct a census of the bison population, administer veterinary treatments and record the health of each animal. Culling the herd of low-vigour, aged animals, and some calves simulates predation and maintains herd size at optimum numbers for the amount of land available at the TGP.

• Calves born in 1999: 228 head of which there were 124 females and 104 males.
• Red Calves¹: zero.
• Calving Rate²: 70-percent.
• Bison at Roundup³: 945 head.
• Known Absentees: 7.
• Number sold: 78 head.
• Number Purchased⁴: 62 from Fort Niobrara, Nebraska; Cross Ranch Preserve, South Dakota; National Bison Range, Montana; and Samual Ordway Memorial Preserve, South Dakota
• Over-wintering Herd Size: 953 head.
• Expected Spring 2000 Calves: unreported.
• Bison Pasture Annual Acreage: unreported.
• Maximum Weight: 1,622 pounds - 1993 born bull.
• Minimum Weight: unreported.

Acknowledgements

Facts and figures for this article are drawn from information distributed to docents of the Tall Grass Prairie Preserve for dissemination to the public.