"I like the grab-bag aspect of it, too," Spencer says.  "There are more than just mallards to shoot.  There are gadwalls, scaup, pintails and all the divers.  You never know what you'll shoot at next, and that adds to the fun."

Big-river hunting requires specialized skills, starting with the ability to locate hunting areas with concentrations of ducks.

"Where you hunt depends a great deal on weather conditions," Spencer says.  "If a blue norther passes through with a calm, cold high-pressure system behind it, look for hunting areas close to current, because that's where open water will be.  If it's rainy and windy, look for sheltered places where ducks find protection from the elements.  Hunt on the lee side of islands or behind dikes or levees.  If the weather's too frigid, and it's raining and windy, too, then just stay home."

Spencer believes in the efficacy of large decoy spreads when hunting big rivers.  "In timber, you hardly need decoys," he says, "because when you see ducks, they're in working or shooting range.  Big water is different; you may see a flock of ducks two miles away, and they must be able to spot your spread.  You need a visual attractor, and the more decoys you've got, the better your visual attraction is.  Take as many decoys as your boat can hold, but no less than three or four dozen."

Loud calling is a prerequisite for big-river hunting. Since the ducks are not resting, noisy calling gets traveling ducks to come in.

In some situations, unless a hunter is a good caller, he's better off letting the decoys do the work.  But that doesn't often hold true on the river where good, loud calling is necessary.

"Forget the feeding call," Spencer says, "because river ducks are resting, not feeding.  The highball is all that's needed, and make it loud."

Spencer usually hunts from a camouflaged boat.  "Most of my hunting is boat stuff," he says, "because it's difficult to find a place on shore to set up a blind.  I usually hunt from a boat that's hidden in some bushes or other cover.  A 14- to 16-foot wide-bottomed boat is ideal.  It needs to be adequately powered but not overpowered -- 25 to 35 horses is about right."

Safety is the most important consideration when hunting big-river ducks.  The sport is inherently dangerous.  Safely practiced, river hunting presents no problem, but there's little room for error.

For high-flying river ducks, you need a visual attractor, and the more decoys you've got, the better your visual attraction is.

Spencer notes each passenger should wear a personal flotation device, and the boat operator should wear a kill switch to stop the engine if he falls or is thrown overboard.  When boating at night, run slowly, always watching for other boats and obstacles like wing dikes and sandbars.  The motor and batteries should be in tip-top shape, but carry paddles for each hunter.  Also pack a waterproof fire-starting kit and some high-energy emergency foods like chocolate bars.  And always file a trip plan with a friend or relative.  Let them know where you're going and when you plan to return.  Then, if you get stranded, someone knows where to start searching.

If you measure success by the number of ducks killed, big-river duck hunting probably isn't for you.  But there are many positive aspects to this arduous sport.  Wind, spray and open space are heady wine for duck hunters.  You're out there alone, without competition.  You see wild places and wild things -- eagles, geese, the occasional deer and, if you're lucky, ducks -- lots of them.  But that plays second fiddle to just being there.

"A big river has a way of making a man in an open boat feel very small and vulnerable," Jim Spencer says.  "That's a good thing to be reminded of every once in a while."