Fall cleanup

Lake Maria State Park

10 a.m.-3 p.m. Saturday

Join park staff and the Friends of Lake Maria to prepare the park for winter. The to-do list includes clearing trails of debris and removing buckthorn. Dress for the weather, wear sturdy footwear, bring work gloves; tools will be provided. Lunch, too, is provided. Registration required; call 763-878-2325. (mndnr.gov/lakemaria)

Tundra swan field trip

Whitewater State Park

10 a.m.-noon Saturday

Early in November each year, migrating tundra swans stop over at the Upper Mississippi National Wildlife and Fish Refuge on their eastern flight to the Chesapeake Bay watershed. Meet with a naturalist at the park visitor center for an introduction, and then join the vehicle caravan through the Whitewater Wildlife Management Area to Weaver Bottoms on the Mississippi River for a view of the swans. Binoculars, spotting scopes and handouts are available. Bring your own transportation. (1-507-312-2300, mndnr.gov/whitewater)

Tech nature

1-3 p.m. Saturday

Minnesota River Valley National Wildlife Refuge

There are apps available for smartphones and tablets created for enjoying nature or engaging in citizen science projects. Learn what they are and how to use them from U.S. Park Service ranger and birder Sharon Stiteler.

Bring your smartphone or tablet, and dress for the outdoors.

Registration is encouraged through the refuge Facebook page. Go to events. This program returns Dec. 15, Jan. 1 and Feb. 16. (952-854-5900, bit.ly/mnvalley)

Sunset photo hike

Minnesota River Valley National Wildlife Refuge

3:30-5:30 p.m. Saturday

Photographer Don Tredinnick (frozenhiker.com/photo-hikes) will lead a hike and photo session. Participants will experiment with capturing sun bursts through the trees and some long shadow landscapes. Bring a tripod to help with long exposures. Call 952-854-5900 to check on the program's status in inclement weather. (bit.ly/mnvalley)

Bird banding

Eastman Nature Center

9 a.m.-noon Saturday

See wild songbirds up close as they are carefully trapped, studied, banded and released. (763-694-7700, threeriversparks.org)

Night biking

Elm Creek Park Reserve

6-9:30 p.m. Monday

Take on 10-14 miles of single-track trail in a time-trial format and self-seeding. Races rotate among Elm Creek Park Reserve, Lake Rebecca Park Reserve and Murphy-Hanrehan Park Reserve. Preregistration cost is $12; $15 the day of the race. Call 763-559-6700. Registration on race day opens at 6 p.m., with the race at 7 p.m. Helmets and lights required. (threeriversparks.org)