Outdoor Discovery programs, hosted by the Butler County Parks and Recreation Department, will present the final program of the summer, "Barn Owls," at 7 p.m. tonight in the Carousel Shelter at Alameda Park, off New Castle Road. The Moraine Preservation Fund, a volunteer organization, will host a presentation about the Barn Owl Reintroduction Program. Admission is free. Call 724-284-5383 or visit www.co.butler.pa.us.

Jennings Environmental Education Center, Route 528 near the intersection of routes 8 and 173, is open from 8 a.m. to 4 p.m. weekdays and on weekends as scheduled. The trails are open daily from sunrise to sunset for hiking. Call 724-794-6011.

Moraine State Park will be the site of a "Treasure Hunting Geocaching" at 11 a.m. Saturday; meet the park naturalist at the Pleasant Valley picnic area on the South Shore. "Hummingbirds: The Jewels of the Air" will take place at 2 p.m. Sunday at Pavilion 7 located at McDanel's Launch on the North Shore. Call 724-368-8811.

Venture Outdoors North office in Zelienople will host Family Camping for Tykes from Friday through Sunday at Moraine State Park. Visit www.ventureoutdoors.org.

Todd Nature Reserve in Sarver will host a Bird Area Monitoring Walk at 8 a.m. Saturday and Wednesday at Butler-Freeport Trail. Meet at Monroe Road, the trailhead in Sarver. "The Trees of Todd Nature Reserve" will take place from 2 to 4 p.m. Saturday; cost is $2 for members; $5 for nonmembers. A Stream Safari is planned for 2 to 4 p.m. Sunday; cost is $2 for members; $5 for nonmembers. An Owl Prowl is set for 8 to 10 p.m. Wednesday; cost is $2 for members; $5 for nonmembers. Call 412-963-6100.

<B>Star Parties</B>, sponsored by the Amateur Astronomers Association of Pittsburgh, are scheduled to start, weather permitting, about 8:20 p.m. Friday and Saturday at the Nicholas E. Wagman Observatory in Deer Lakes Regional Park, near the village of Russellton. Admission is free, though donations are accepted to help cover the costs of operation. Call 724-224-2510 or visit the Web site, www.3ap.org.

<B>McConnells Mill State Park</B> in Slippery Rock Township, just of the county line into Lawrence County, is open from 11 a.m. to 3:30 p.m. Fridays and 11 a.m. to 5 p.m. Saturdays and Sundays. A Hike Along the Millstream is set for 1 p.m. Sunday. This two-mile hike takes place over moderately rough terrain along Slippery Rock Creek. Park at the Kildoo Picnic Area and walk the path down to the mill courtyard to meet the park naturalist. An Owl Prowl will take place starting at 8 p.m. Wednesday. Take a flashlight and wear sturdy shoes and meet park staff at the Hell's Hollow parking lot. Call 724-368-8811.