In the history of North America, only humans, disease, predation, and starvation have successfully controlled bison numbers. Hunting outside the park is the preferred method for controlling the population today, but bison need greater access to land in order to disperse beyond our boundaries and pioneer new areas. Currently, the area where bison can be hunted is very small, and bison often respond to the hunting pressure by returning to the security of the national park (where hunting is prohibited). Our capture and shipment operation makes up the difference when hunting outside the park fails to meet reduction targets set by the IBMP managers.