Try nature geocaching in a free search organized today at the McNary National Wildlife Refuge near Burbank.

A limited supply of GPS units will be available to help participants follow clues to find 21 of nature's treasures along the McNary trail from 9 a.m. to noon. There is no cost.

The refuge's Environmental Education Center is at 311 Lake Road. From the Tri-Cities go east on Interstate 182 and Highway 12 to Burbank. Turn left at the Humorist Road stoplight and then left on Lake Road.