Jennings Environmental Education Center, 2951 Prospect Road, Brady Township, plans An Owl Prowl and Woodcock Watch, hosted by the Bartramian Audubon Society, at 7 p.m. March 28. “Nature Detectives: Invaders of the Lost Park” at 2 p.m. April 5; pre-registration is required by April 3 at http://events.dcnr.pa.gov or by calling 724-794-6011. Take Back the Woods: Battling Invasive Species needs volunteers from 9 a.m. to 1 p.m. April 18. Pre-registration is required by April 11.

Moraine State Park will be the site of a Winter Weeds Walk at 1 p.m. Saturday from the South Shore park office. The walk to the Sunken Garden Trail will be an easy 1.5-mile hike along Lake Arthur looking for dried grasses, seedpods, and other treats of nature. Meet at the South Shore park office.