Acorns have rattled off the oak trees, and sumac and a few maples are starting to glow red with autumn color. Take advantage of crisp skies and cooler weather while ziplining, hiking, riding or paddling among fall colors as they ripple from northern Minnesota in mid-September down to southern Minnesota by mid-October. Check the Minnesota Department of Natural Resources Fall Color Finder (dnr.state.mn.us/fall_colors) for weekly updates. Don’t forget to look up and keep your ears open for gathering flocks of cranes, songbirds, geese, ducks and more as birds head south.

September

Watch hawk migration

Lake Superior views alone are worth a trip along Duluth’s beloved Skyline Drive, but elevate that experience Friday through Sunday with the annual Hawk Ridge Birding Festival, which has signup for multiple events. Call or check online for availability. Other options at the observatory include the weekend public programs that generally run one hour and include hawk-watching. (1-218-428-6209; hawkridge.org)

Seek treasure

Combine fall colors with high-tech treasure-hunting by joining the Million Shades of Autumn geocaching event at William O’Brien State Park from 10 a.m. to 4 p.m. Saturday. The Minnesota Geocaching Association will lead the daylong program. Check the Minnesota Department of Natural Resources site for info on other state park geocaching events. (651-433-0500; dnr.state.mn.us)

Follow fat-tire enthusiasts

The 2,100 coveted spots for Chequamegon Fat Tire Festival’s grinding 40-mile race through forest near Hayward and Cable, Wis., are taken, but you can join the family activities and cheering sections on Saturday or sign up for guided 8- to 12-mile rides on Sunday with the Cable Area Mountain Bike Association. (cheqfattire.com)

Find a fire tower

If you’re craving a bird’s-eye view of fall colors, check out Minnesota’s public fire towers. You might feel a sway in the wind and want to hold onto your hat after the long climb up at Whitewater, Itasca, Mille Lacs and St. Croix state parks, as well as Big Bog State Recreation Area. If you prefer a guided activity, join the Fall Color Fire Tower Hike on Saturday at Itasca State Park. (dnr.state.mn.us)

October

Make a run for it

One of the nation’s top 10 U.S. marathons based on number of finishers and called one of the "most beautiful urban marathons" (by Runner's World), the Medtronic Twin Cities Marathon attracts more than 300,000 spectators to cheer on runners Oct. 4. The weekend also includes a health and fitness expo at St. Paul River­Centre and 5K or 10K race options Oct. 3. (651-289-7700; tcmevents.org)

Cruise the St. Croix

Get on the St. Croix River for some of the state’s most dramatic scenery as it flows through a glacier-carved canyon with formations such as Lion’s Head and Old Man of the Dalles. Catch a shuttle for a canoe paddle between Minnesota’s Interstate and William O’Brien State parks or opt for a 30- or 80-minute paddlewheel boat trip (651-465-6365; wildmountain.com).

Gear up for ski season

Sell outgrown or underused ski equipment and find deals on new gear, outdoor clothing, lessons and passes for the upcoming season at Afton Alps Fall Fair and Ski and Snowboard Swap Oct. 3-4 and 10-11 in Hastings. Families can join a hayride and paint pumpkins (1-800-328-1328; aftonalps.com). Wild Mountain in Taylors Falls also has a swap Oct. 4-5, and will be selling apples from Sunrise River and offering half-price ride tickets with an online coupon. Other metro-area swaps include Buck Hill on Sept.25-27 in Burnsville.

Back in the saddle

Soak up fall colors from the back of a horse with trail rides through the rolling 1,600-acre Bunker Hills Regional Park. There also are lessons and day camps. Andover’s Bunker Park Stable welcomes first-time riders, but participants must be at least 8 years old and 52 inches tall. (763-757-9445; bunkerparkstable.com)

Ride or run to Stillwater

Bike or run the 5.9-mile Brown’s Creek Trail that follows the former Minnesota Zepyhr train route into Stillwater. Anyone up for a long-distance trek can continue on the Gateway Trail that runs about 11 miles from northern Washington County to St. Paul (gatewaybrownscreektrail.org). Time a visit with Stillwater’s Fall Harvest Fest Oct. 11-12 (harvestfeststillwater.com).

Zip down the valley

Take a scenic drive through the Minnesota River Valley to tiny Henderson where you can whir across 14 ziplines with Kerfoot Canopy Tour or paddle the river (952-873-3901; kerfootcanopytour.com).

November

Seek tundra swans

Listen and look for the snow-white flocks that gather along the Mississippi River in southeast Minnesota before heading south. Good places to watch: The observation platform at Rieck’s Lake Park just north of Alma, Wis., and along Hwy. 61 near Weaver, Minn., south of Wabasha. For a guided outing, join a bus tour from 9 a.m. to 3 p.m. Nov. 14. Register by Nov. 7 (507-494-6238; dnr.state.mn.us).

Plan the next adventure

Get revved up to climb and explore with the Outdoor Adventure Expo through Midwest Mountaineering and the University of Minnesota on Nov. 20-22 in Minneapolis. It’s free to check out presentations and more than 60 exhibits. Tickets go on sale Oct. 24 for the Banff Mountain Film Festival World Tour (612-339-3433; outdooradventureexpo.com). By the way, it’s never too late to plan ahead: The spring version of the expo is April 22-24.

Winter tune-up

Get your vehicles serviced for cold weather and icy road trips; sharpen skis and skates; relocate hats, mittens, base layers and boots; get out sleds and snowshoes; and make sure you have everything ready for winter fun once the first snowflakes fall.