SIOUX CITY | The Loess Hills Audubon Society and Iowa Natural Heritage Foundation plan to lead a hike of the Spirit Knoll Preserve at 9 a.m. on May 4.

It starts at the west entrance of the preserve, off Highway 12, three miles north of Stone State Park, 5001 Talbot Road.

The Iowa Department of Natural Resources began operating the site last year. It will become a state preserve and open to the public after an archaeological survey is complete.

Call 515-288-1846 for more information.