1 Three miles of Pike Fort Snelling State Park, Sept. 7, 10 a.m.-noon Join a naturalist for a 3-mile walk around Pike Island, a great place to spy wildlife while stretching the legs. Head for the confluence of the Minnesota and Mississippi rivers — a magnificent setting for a workout — and back to the visitors center. 612-725-2724 or www.mndnr.gov.

2 Charity polo match for Freedom Farm, Sept. 7, 11 a.m.-3 p.m. Head to BlackBerg Ranch, 1980 Sally Av., Watertown, for a day of family-friendly activities benefiting Freedom Farm. The event includes a kids' polo match, a hat contest and a divot stomp. Freedom farm and its horses help kids and adults with physical, mental and emotional challenges. $10. 952-955-2505 or www.freedomfarmmn.org.

3 Pothole tour

Interstate State Park, Sat. and Sun. through Sept. 29, noon-1 p.m.

Take a naturalist-led tour of this pothole-pocked park. Formed 10,000 years ago, Interstate's signature potholes are the work of ancient lava lakes and gushing glacial waters. All ages. 651-465-5711 or www.mndnr.gov.

4 Back-deck birding St. Croix State Park, Sept. 8, 11 a.m.-noon

Meet with a naturalist on the back deck of the park's main lodge for a talk on birding basics, plus a short tutorial on the St. Croix River's important role in fall migrations. Open to all ages, including children. 1-320-384-6591 or www.mndnr.org.

5 Women's river rafting

Coon Rapids Dam Regional Park, Sept. 8, 1-4 p.m. Hop aboard a 10-person inflatable river raft for a naturalist-led tour of the Mississippi's birds, backwaters and shorelines. Stop for a snack on one of the river's islands. Ages 18 and older. $35. Registration required. 763-559-6700 or www.threeriversparks.org.