Bison have been characterized as a nomadic animal always in search for new and better resources. The constant movement by bison results in the possibility that grazed areas will have varying lengths of days before being revisited. Studies where bison have access to large ranges have demonstrated that revisit times are highly variable resulting in days and weeks of rest for many of the previously grazed areas. Periodic rest of grazed areas is one of the best treatments to prevent the effects of overgrazing. How exactly this movement and rest by bison benefits vegetation health when bison are on smaller sized pastures is not known and whether the unregulated movement by bison will prevent overgrazing has not been demonstrated.
Bison are efficient grazers taking little time to meet their intake when on good pasture.
When not grazing bison will spend a substantial amount of time doing other social activities especially during rut. When bison do graze they form a grazed patch in the ungrazed vegetation. Studies have shown when stocking rates are low the average patch size is small and patches are spread out across the area and not clumped together. As stocking rates go up patches start coalescing together. The significance of bison grazing small patches on the health of vegetation is not known at this time, but theory does point to this patch grazing contributing to sustainability of rangeland.