ABERDEEN, S.D.

Waterfowl filled the predawn sky from horizon to horizon, ducks and geese crisscrossing from every direction at various altitudes in a chaotic, frenzied flight.

Six of us lay on our backs, hidden in camouflaged layout blinds, mesmerized by the aerial stunt show.

Ten minutes later, the sun now lighting a golden field of corn stubble, thousands of barking snow geese lifted off the ground a quarter-mile to the west, and the tornado of birds quickly drifted overhead, eyeing our 1,000 decoys.

"Take 'em!" hollered Jason Swartz.

A volley of shots exploded, and a half-dozen birds fell from the sky. The rest flew off.

"That was breathtaking,'' said Mike Porter, 59, of Minneapolis.

"That tornado of geese is something everyone should see,'' said Paul Lewis, 57, of Mendota Heights, who was hunting with his son, Brad, 30, of Minneapolis. "There aren't too many days you can lie on your back and see that kind of show.''

The spring migration of snow geese and other waterfowl definitely is a four-star show.

But a weekend trip to northeastern South Dakota last week also underscored the difficulty of hunting snow geese, one of the longest-lived and wariest of waterfowl. Guides Swartz, 39, and Cody Bruns, 29, both of the Aberdeen area, scouted the region and found an area holding thousands of birds.

But despite putting out 1,000 decoys, including multiple ''flying'' decoys on rotary machines powered by marine batteries, and with two MP3 soundtracks blasting snow goose calls, our group of six bagged just 16 birds in 1½ days of hunting.

Flocks of mallards, pintails, redheads, teal, Canada geese and white-fronted geese thrilled us, flying low into our decoys — set around a small patch of water in a vast field of corn stubble. Some ducks landed. But rarely were the snow geese fooled.

"They are definitely the smartest species of waterfowl,'' Swartz said. "Some are 20 years old; they've seen this all before.''

Still, we were pleased to see swarms of waterfowl, and to get some shots.

"Any day you can pull the trigger on snow geese is a good day,'' Bruns said.

Not reducing population

This is the 16th year the U.S. Fish and Wildlife Service has allowed a spring "conservation order,'' or spring hunting season, to try to reduce the light goose population, which includes snows, blue geese and Ross' geese. The population has ballooned during the past 50 years to an estimated 15 million. Especially worrisome to wildlife officials is that the geese have degraded their fragile subarctic nesting grounds on Hudson Bay, damage that continues today. And agriculture expansion in their migration and wintering areas has provided the birds an almost unlimited food supply.

The special season allows hunters almost unlimited hunting opportunities. They can use unplugged shotguns and electronic calls, and there are no bag limits in Minnesota, South Dakota, North Dakota and many other states. The result: About 1.5 million light geese are killed each spring in the Central and Mississippi flyways.

But that's not nearly enough.

"We wanted to reduce the adult female survival by 50 percent,'' said Steve Cordts, Minnesota Department of Natural Resources waterfowl specialist. "It was thought that would reduce the population. But our harvest rates are extremely low. Even with the conservation order, there's just no way we can shoot enough.''

Minnesota is on the fringe of snow-goose migration routes. The DNR sold 1,400 $3.50 spring permits last year, and an estimated 770 hunters killed about 2,400 light geese. Many thousands more pass through South Dakota, where about 7,000 hunters, including 4,000 nonresidents, dropped a record 168,000 light geese in 2013.

This year, Minnesota's season runs until April 30, South Dakota's until May 4 and North Dakota's until May 18.

The geese generally fly in large flocks, and they can live 20 years. "They've played the game before,'' Cordts said. Said Rocco Murano, South Dakota Game Fish and Parks waterfowl specialist: "They've even learned to recognize electronic calls, too.''

The price of admission

For more than two hours Friday night, until well after dark, we set out decoys. It was a slow process because it required using two cordless drills to bore holes in the rock-hard frozen ground for our windsock decoys.

Then we were up at 3:45 a.m. to drill more holes for another 300 decoys, then hunted all day.

Sunday we slept in — until 4:30 — and then the waterfowl gave us a repeat performance, with a huge flock of snows again drifting overhead within shotgun range shortly after sunrise.

"That was worth the price of admission,'' Swartz said.

Said Paul Lewis: "That was a spectacle.''

Doug Smith • doug.smith@startribune.com

Twitter: @dougsmithstrib