CLARK, S.D. – Whitecaps rolled on nearby ponds as a cluster of 17 snow geese flew directly into a powerful east wind, dropping toward a spread of twitching paper decoys and the amplified noise of an electronic goose call.

Just when the birds entered shotgun range, four hunters popped up in unison from an underground pit hidden within the display. Amid a rapid-fire volley of steel pellets, two of the birds fell, sailing with the wind as they did.

The storm-shortened hunt late last week in a farm field four hours west of the Twin Cities inspired awe over the migration of an overabundant wildlife species. The trip also reinforced a belief shared alike by hunters and natural resource managers that flocks on the leading edge of the midcontinent snow goose migration are loaded with experienced fliers difficult to fool.

"The breeders are pushing up first, trying to get to the arctic as soon as possible to breed,'' said Josh Dooley, a wildlife biologist and goose specialist with the U.S. Fish and Wildlife Service.

Those leading birds, he said, are older and wary of hunters.

For population control purposes, snow geese can be harvested nine months out of the year. Their only respite from hunters comes during nesting season in the high arctic and while staging in the subarctic. The 10 million to 12 million birds that fly over parts of Minnesota, North Dakota and South Dakota spend winters in Texas, Louisiana and Arkansas.

"They're blasted all the way down and back up,'' Dooley said.

No limit

Despite the vagaries of spring seasons in which the birds push north as quickly as they can depending on snow and ice conditions on the ground, early season hunters in the U.S. and Canada typically account for 50 to 60 percent of the annual harvest of snow geese and similarly light-colored Ross's geese. In Minnesota, South Dakota and North Dakota the bottom-line rule for the spring hunt is "No limit.''

The spring migration opened to U.S. hunters in 24 states in 1999 as a conservation measure. It was part of a historic multinational effort to save fragile arctic habitats in far northern Canada and Alaska from irreversible damage caused by exploding light goose populations. New rules provided flexibility for hunters to use normally prohibited electronic goose calls and extension tubes on their shotguns for firing more than 10 shells without reloading.

Simply stated, the early seasons were established to utilize hunters as free labor to control habitat degradation on the tundra. Or as some hunters like to say: "Kill a snow goose, save a polar bear.''

Flying high

For two days late last week in the narrows of a 5-foot-deep ground pit, our trio admired wave after wave of migrating ducks and geese. Small bands of Canadian honkers flew by regularly, within easy range. Just as often, pintails, redheads and other ducks darted around us with abandon. The ducks flew even when winds of 40 miles per hour mixed with falling snow.

For Tim McBride of Fond du Lac, Wis., it was the first experience attempting to lure large, high-flying flocks of snow geese to hundreds of decoys. Set for us by local hunter Josh Craig, we imagined the spread would be viewed from above as a pop-up goose carnival.

Scott Ward of Inver Grove Heights and I were situated in a similar pit the previous spring. But in 2017, we arrived in South Dakota on the last dwindling days of the migration. Now we were hunting leading-edge flocks too numerous to count — each one more wondrous than the next for the way it billowed across the sky.

But just when a collection of geese would take an interest in our field, they'd intersect with another passing flock and get diverted. At other times, numbers of young geese would clearly set their wings to lower themselves into the decoy spread, only to be magnetized back into the flock by stubborn adults who peeled away.

In hindsight, we should have taken more shots as groupings of snow geese advanced toward us. Instead, we waited in vain for the birds to fully commit to the decoys. Invariably, they shifted out of range in the blink of an eye.

When weather conditions worsened — ultimately blanketing our decoys with 8 inches of snow — we abandoned the trip with only four snow geese in our bag.

Still growing

Dooley of the Fish & Wildlife Service said the growth rate of the midcontinent snow goose population has slowed in the past couple of years. The big difference is that colonies of the birds aren't producing as many goslings as they once did, he said. But last year's hatch increased, and the overall assessment is that the growth rate has diminished only in comparison to earlier decades.

Moreover, wildlife biologists have abandoned the survey method used in the 1990s to estimate what was then believed to be 3 to 5 million lesser snow geese in the midcontinent region. New methods put the population closer to 12 million adult birds.

Meanwhile, the population trend has increased for snow geese that migrate within the more westerly flyway that serves nesting territories in northern Alaska, Wrangel Island and Russia.