Trees of the Big Woods

Nerstrand Big Woods State Park

10:30 noon Saturday

Join a master naturalist on a hike featuring the park's varied hardwoods, including sugar maple, basswood, oak, hickory, aspen, elm and ash. Discover how leaves change color and learn tree identification tips. A vehicle permit is required to enter the park. (1-507-333-4840; dnr.state.mn.us)

Birding hike

Fort Snelling State Park

9-11 a.m. Saturday

Join a park naturalist for a birding hike after learning how to use a field guide and binoculars. Equipment provided. A vehicle permit is required. Registration required. Call the park or e-mail Krista.Jensen@state.mn.us (612-725-2724; dnr.state.mn.us)

Bird migration

Glacial Lakes State Park

10-11:30 a.m. Saturday

Many of Minnesota's migratory birds have either already left or are preparing for their journeys to warm locations. Meet the park naturalist at the overlook in the picnic area to learn more about birds, and then go in search of some. (1-320-239-2860; dnr.state.mn.us)

Adapted sports day

Fish Lake Regional Park

1-4 p.m. Sunday

Three Rivers Park District is committed to providing recreational opportunities to people of all mobility levels. Sunday is a sports demonstration day. Try adapted mountain bikes, kayaks, archery equipment and geocaching. Cost is $8. Reservations are required by Friday. Call 763-559-6700. (threeriversparks.org)

Interpretive bike ride

Gateway State Trail

10 a.m.-noon Sunday

Meet at the south end of the Maplewood Community Center parking lot. Contact Linda Radimecky at 651-231-6968 or by e-mail at Linda.Radimecky@state.mn.us for more information.

Glacial pothole tour

Interstate State Park

Noon-1 p.m. Sunday

A naturalist will lead participants over, under and through rock features at the park. Discover how lakes of lava and glacial waters formed the unique glacial potholes. The hike involves stairs and uneven terrain. All ages are welcome. Meet at the visitor center. (651-465-5711, dnr.state.mn.us)