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)