1 Volunteer cleanup and buckthorn removal

Seminary Fen, Oct. 26, 9 a.m. to noon

Help remove buckthorn (and trash) from Chanhassen's Seminary Fen, one of the rarest forms of wetland in the country. This peat-rich land type supports unusual plant and wildlife species. Participants need good mobility and a sturdy pair of rubber boots. More information at 952-227-1133 or www.mndnr.gov.

2 Kathio 1,500 B.C.

Mille Lacs Kathio State Park, Oct. 26, 10:30-11:30 a.m.

The park becomes a time machine during this short naturalist-led tour. See where archaeologists discovered evidence of a village from the 1600s and a campsite from more than 3,000 years ago. Meet at the park's interpretive center. 1-320-532-3523 or www.mndnr.gov.

3 Creatures of the night

Lebanon Hills Regional Park, Oct. 26, 6:30-8:30 p.m.

All animal species are uniquely adapted to maximize their rates of survival. Join a naturalist to hike the park at dusk while learning how the resident animals have adapted to darkness and night life. All ages. $8. More information at www.dakotacounty.us/parks.

4 Animal skins and skulls

Fort Snelling State Park, Oct. 27, 1-2 p.m.

Perfect for families, this hands-on educational program invites participants to examine the skins and skulls of various species living at Fort Snelling State Park, learning about their adaptive traits in the process. 612-725-2724 or www.mndnr.gov.

5 Mountain bike at night

Elm Creek Park Reserve, Oct. 29, 6:30-9:30 p.m.

Perfect for intermediate mountain bikers, this nocturnal time trial covers 10.5 miles of twisting trail and single-track. Helmets, taillights and two headlights per cyclist are required. Ages 14-plus. $12-$15. Registration required; 763-559-6700 or www.threeriversparks.org.