With little wind blowing early Saturday morning, most of the 300 decoys the hunters had put out were still and lifeless.
But there were some noticeable exceptions.
Six of the imitations were dipping and darting around on the surface of the marsh near the Squaw Creek National Wildlife Refuge, creating life-like activity on the water.
Why the stark contrast? Pan to the blind, where Brett Ware was at the controls, using a remote device to create movement in the battery-operated decoys he helped design.
"It's like those remote-control boats we used to play with when we were kids," said Ware, who runs the Ultimate Hunter Co. that sells the Swim'n Duck decoys. "I can sit in the blind and use a controller and get the decoys to go forward, backwards, left and right.
"When it's calm, it really adds movement to the decoys. And that's what attracts the ducks."
Motion decoys are nothing new. Decoys with wings that spin or tip in the wind have been around for several years. But decoys that actually swim the distance of a tether, turn and bob are something different.
John Iden, who runs a hunting guide service, first came up with the concept and brought it to Ware, who then refined it before coming up with a prototype.
The moment that prototype started swimming, it produced impressive results.
"Ducks circle and check things out before coming in," said Ware, who lives in Maryville, Mo., and is an instructor at Northwest Missouri State University. "They want to make sure everything is OK before they commit.
"With these decoys, we were amazed at how quickly they would commit. A couple of times, we would go from having no success at all with traditional decoys to getting lots of ducks to come in with our automated decoys.
"We even did tests, moving the location of the automated decoys, and the ducks would still land near where they were.
"That told us we were on the right track."
Ultimate Hunter, which is based in Maryville, put the Swim'n Duck decoys on the market in 2004. Today, it is found in major hunting outlets such as Cabela's and Bass Pro Shops and is known nationwide.
The decoys sell for about $100 apiece and are available in mallard, pintail, wood duck and widgeon models as well as Canada goose and snow goose imitations.
Ware also has designed fishing lures, which he sells under his Ambush Lures company. But at this time of the year, he concentrates on his decoys.
"I used to hunt with a jerk-cord," Ware said. "I would tie a line to three or four decoys, then jerk that cord to get my decoys to move.
"Now I have this. The goal is the same: to give the impression that there are ducks on the water, moving and stirring up the water.
"Especially on days when it's calm, these automated decoys can be deadly.''