MAMMOTH HOT SPRINGS, Wyo. (AP) – Yellowstone National Park officials have closed a bison area as preparations get underway for reducing their number in advance of the annual bison migration.

The National Park Service temporarily closed the area in the northern section of the park near Gardiner, Montana, after officials approved a winter operations plan that calls for a reduction of Yellowstone’s current population of 5,500 bison. They say the state of Montana has limited resources for natural bison migrations from the park onto state lands.

In previous years, the herd has been reduced by allowing public and tribal hunting outside the park, and capturing bison to be transferred to Native American tribes for processing and distribution of meat and hides to their members. However, bison managers say that is not enough.