LAKE PRESTON, S.D.

Several thousand squawking snow geese swirled over the field like a huge white whirlpool, then landed and fed on the remnants of last fall's corn harvest.

More white geese, their black-tipped wings locked, spiraled down from an azure sky to join them. Three of us, clad in camouflage and cradling shotguns, hunkered on the lip of a grassy ravine not 30 yards away and watched the spectacle with awe.

When dozens of birds glided even closer, we jumped up and fired. The startled flock instantly lifted off in one great barking mass and headed skyward over the frozen South Dakota prairie.

"Wow, that alone was worth the trip,'' said Don Sauter, 54, of Arlington, Minn.

Sauter's son, Ryan, who had approached the flock from the east, joined us. We collected nine geese -- among 21 we shot over two days last weekend in the special spring light goose hunt. Not bad, considering the migration in South Dakota is just beginning.

However, just witnessing the spring waterfowl migration is inspiring. The countryside was teeming with wildlife.

We saw tens of thousands of snow geese, white-fronted geese, Canada geese, mallards -- even black clouds of red-winged blackbirds that stretched across the horizon.

"That's unbelievable,'' Don Sauter said when we encountered a bee-like swarm of black birds. "I've never seen anything like it.''

The few geese we took home were just white icing on the cake.

Snow geese targeted

This year is the 10th special spring light goose hunting season -- officials call it a "conservation order.'' It is offered in about two dozen states, including Minnesota, Iowa and the Dakotas.

The goal when federal officials launched it in 1999 was to reduce the population of snow geese because the growing population was damaging its arctic nesting grounds. The special hunts include liberal to non-existent bag limits and hunting methods not legal during regular waterfowl hunting seasons, such as electronic calls and shotguns that hold more than three shells.

The spring hunts have increased the harvest of light geese. But hunters haven't been able to reduce the population, said Dave Sharp of the U.S. Fish and Wildlife Service.

"The population is not declining, but the growth rate has been cut,'' he said. "We certainly have fewer geese heading north.''

The objective was to reduce the mid-winter population to about 1.5 million. The most recent estimate puts that number at 2.6 million. Some believe it is much higher.

The population continues to grow slightly even though hunters in both the regular fall seasons and the spring hunt are killing more than 1 million light geese yearly.

Fewer goose hunters

But the number of spring snow goose hunters has been declining recently.

About 54,000 hunters pursued mid-continent snow geese in the spring of 2006, down from a high of about 75,000 in 2000. In South Dakota, spring snow goose hunters numbered about 5,300 last year, compared to 9,300 in 2002.

"The novelty is starting to wear off,'' said Spencer Vaa, waterfowl biologist with the South Dakota Department of Game, Fish and Parks.

One reason might be because snow geese are notoriously difficult to kill. They're hunted from September to May, from Canada to the Gulf Coast and back.

"They are very wary birds,'' Vaa said. "They're getting harder to kill.''

We got up at 3 a.m. one morning, set out 700 snow goose decoys in a corn field, then snuggled into blinds. Three electronic calls (powered by small MP3 players) mimicked the sound of thousands of snow geese.

The results: We shot one low-flying snow goose. Several other flocks flew past well out of shotgun range.

"They've seen this all before,'' Don Sauter said.

But mallards, white-fronted geese and Canada geese flew past, giving us a close-up glimpse of the spring migration.

"Isn't it just great being out here and seeing all of this?'' Sauter asked.

Yes, indeed.