The country road feels dark and desolate on the way to the 31,000-acre Sherburne National Wildlife Refuge. Maybe it’s the effect of that eerie transition time. At 6 a.m. on the last day of September, the chirps and titters of all the critters have gone quiet. The day crew has yet to start.

We want to be there when it does. Wildlife biologist Tony Hewitt drives slowly, crunching along a gravel road until we reach the St. Francis pool.

“There they are,” he says, pointing toward vague shapes still veiled by night. A few hundred sandhill cranes roost by the water — a sight that’s been on my autumn bucket list for years. We pause a few minutes, roll up the windows to ward off the chill and marvel at the cranes’ amazing comeback.

In the mid-1940s, their numbers were down to about two dozen nesting pairs in the whole nation. In the past 10 years, they’ve made enough of a surge here and across the country that Minnesota even allows some crane hunting in the northwestern part of the state. Thousands of the greater sandhill species, standing almost 5 feet tall apiece, gather at the refuge on their way to Florida and Georgia’s Gulf Coast before the snow flies.

“Last year we had a peak of 6,700 cranes,” Hewitt says. “The year before, it was 7,600.”

I saw my first crane in 1999, but only because I was with the late St. Cloud State biology Prof. Al Grewe, who pointed it out. We were visiting the refuge in March, seeking the first signs of spring. I couldn’t see the crane well — I certainly didn’t spot the distinctive red stripe on its head — but I could hear its distinctive, stuttered ka-a-a-aroo call. I’ve been listening for it ever since.

My family has occasionally heard cranes flying high above our house, about a mile from the Mississippi. One summer we heard a nesting pair in some nearby meadow. More recently we’ve spotted several redheads telescoped above rural fields between central and northern Minnesota.

“Cranes are one of our success stories,” says Hewitt, along with the Canada goose and bald eagles. “They’ve really made a huge comeback.”

We’ve been stopped for less than 10 minutes, squinting into the dark, when Hewitt rolls the windows down again and whispers, “Listen.”

The air, once silent, fills with their chatter. It’s an ancient conversation — clicks and clacks punctuated with squawks and those guttural, stuttered ka-a-a-aroos. I can imagine this sound filling a thick, humid prehistoric swamp. Where the cranes are

I’ve been to the refuge several times over the years to hike prairie trails with my kids and enjoy a changing palette of wildflowers — from purple lupines to fragrant beebalm to yellow coneflowers that nod among the tallgrass.

The refuge, northwest of Elk River and southeast of St. Cloud, was founded in 1965. It encompasses the Anoka sand plain and a transition zone between big woods and tallgrass prairie. The sand plain, which you can clearly see as brown sandy ground here and at nearby Sand Dunes State Forest, was once a sand-bottomed lake on top of a glacier. When the glacier melted, the sand remained behind.

Controlled burns averaging 5,000 acres a year send billowing curtains of smoke into the sky, but they help maintain and rejuvenate the native oak savanna ecosystem. Bur oaks punctuate the wide grassland with a few wetlands dotted with aspen and birch.

The refuge has the 8-mile gravel Prairie’s Edge Wildlife Drive meandering across its rolling terrain, with trails coaxing hikers onto prairie, into woods and to observation decks for watching waterfowl. Binoculars are highly recommended, especially for viewing an eagle’s nest that’s usually visible from public roads (and one of about a dozen eagle nests in the refuge).

“It’s a fairly rare ecosystem,” Hewitt says, referring to only 0.02 percent of the original oak savanna habitat preserved. Prepare for takeoff

Nesting cranes return to the refuge by March or early April each year when the ice is out. They eat a high-protein diet such as snakes, frogs and insects that strengthen the two eggs they lay every year in grass nests. By fall they’ve switched to grains and corn to fatten up for their grueling 2,500-mile migration south.

By late September, cranes that have nested in different parts of Minnesota begin gathering or “staging” at the refuge, roosting along ponds at night. There’s safety in numbers, and if there’s any doubt, a coyote appears and briskly trots along one of the ponds, presumably seeking breakfast.

There are likely more than 1,000 — maybe 2,000 — cranes already gathered on the last day of September, with more on the way through mid- to late October. The refuge has a guided 6:30 a.m. public tour Oct. 19 and 20 to see the cranes depart for the season.

It’s a shame to miss such a rare event. As dawn lightens the landscape, a group of cranes lifts up as easily as dandelion seeds blow in the breeze. Every few minutes, a new flock lifts up, bit by bit, as the pinkish sun appears, ray by ray. The cranes’ morning serenade continues, gaining strength as they shake off sleep and more join in. It echoes across the water and fills the skies around us.

What felt like the middle of nowhere in pre-dawn darkness now feels like center stage. Golden rays of sunshine squiggle across the sky and illuminate cranes gracefully arcing across cotton-candy clouds. Their song’s volume peaks, like Mother Nature’s operatic climax for a heavenly Minnesota morning.

St. Cloud-based travel writer Lisa Meyers McClintick writes about destinations across the Upper Midwest.