COUNTYJennings Environmental Education Center, Route 528, Brady Township, will host a “Spring Warbler” program in two different sessions on May 1, one from 8 to 10 a.m. and one from 10:30 a.m. to noon. Registration is required by April 22. “Spring Wildflowers” will be presented at 2 p.m. May 8. “Take Back the Woods: Battling Invasive Species” will be held 9 a.m. to 1 p.m. Saturday. Call 724-794-6011.Bartramian Audubon Society is offering birding field trips April 23 to the Macoskey Center at Slippery Rock University by calling 724-794-2434; and April 30 to Black/Celery/Pennsy Swamps SGL 194 & 284 by calling 724-794-2434. These trips are free.Succop Nature Park, 185 W. Airport Road, Penn Township, hosts free birding and nature hikes with a naturalist at 9 a.m. Thursdays. Trails open from dawn to dusk. Call 412-963-6100 or visit www.aswp.org.

REGIONStar parties sponsored by the Amateur Astronomers Association of Pittsburgh are to begin, weather permitting, at 8 p.m. Friday and Saturday at the Nicholas E. Wagman Observatory in Deer Lakes Regional Park near Russellton, Frazer Township, Allegheny County. Call 724-224-2510.