River trail

Interstate State Park, 10-11 a.m. Saturday

Wear good hiking shoes and bring water for this 1.25-mile hike that starts at the southern end of the park and ends at the glacial pothole area. Expect rocky footing and hills in places. Recommended for adults. (mndnr.gov/interstate; 651-465-5711)

Carley Bluebell Festival

Carley State Park, 10 a.m.-3 p.m. Saturday

An event devoted to the spring wildflower, it includes trout fishing programs for children, archery for visitors ages 8 and older, walks to check out wildflowers and more. (mndnr.gov/carley; 1-507-312-2300)

Spring bird migration

Mille Lacs Kathio State Park, 1-1:45 p.m. Saturday

There will be a talk and slide show about migration, as well as a lesson on how to use binoculars. You'll also hear tips on attracting birds to your yard. (mndnr.gov/millelacskathio; 1-320-532-3269)

Field skills

French Regional Park, 1-3 p.m. Saturday

Learn geocaching basics and search for delicious treasure: s'mores. Children 17 and younger must be accompanied by a registered adult. Reservations required. Call 763-694-7750. (threeriversparks.org)

Bluebird walk and talk

William O'Brien State Park, 10-11 a.m. Sunday

Take a look inside a bird house to see baby bluebirds, swallows, wrens or chickadees. The walk is a half-mile in length. Bring binoculars. (mndnr.gov/obrien; 651-433-0500)

Bird banding demonstration

Whitewater State Park, 12:30-2 p.m. Sunday

Master bird bander Greg Munson will show how he handles birds for tagging and releases them. Program takes place outside at the visitor center bird feeders. The event will be canceled if it rains. (mndnr.gov/whitewater; 1-507-312-2300)

Bird walk

8-10:30 a.m. Sunday, Minnesota Valley National Wildlife Refuge

Meet at the trailhead in Bloomington for a bird walk led by a volunteer naturalist at the Bass Ponds trails of the Long Meadow Lake unit. Learn about some of the 220 species that stop during their migration south. Birders of all levels are welcome to join. Bring along binoculars, and a field guide if you have one. Meet at the Bass Ponds trailhead. (952-854-5900, bit.ly/owFWS)

'Stump a naturalist'

Eastman Nature Center, 1-3 p.m. Sunday

Try to stump a naturalist with your nature questions and mystery items. Drop in anytime. (763-694-7700, threeriversparks.org)