"Oftentimes, you're going to need a boat, something like a regular V-hull boat to get you upriver," McCreary said. "Plus, you're going to need a decent motor to battle the current. For the most part, while you're not necessarily going to be hunting the main stem of a river, you'll need the boat and motor to get to backwater areas where the water isn't moving too fast."

Many times, getting to where the birds want to be will mean gaining access to prime duck-hunting ground found on private property. That chore is certainly more difficult today than in years gone by, but Renner pointed out that hunters who do their homework to locate a landowner can still receive permission to hunt waterfowl with a polite and reasonable request.

Renner continued that once you've located birds and secured access, late-season duck hunting is a bit more of a scaled-down affair than early-season hunts on bigger waters.

Flocks of ducks that decoy into spring creeks, streams and rivers are typically smaller than the massive flocks that pinwheel around feeding fields. That's why Renner recommended using one to two dozen mallard decoys, as the situation warrants.

McCreary agreed, noting that mixing in a few green-winged teal decoys never hurts a late-season spread.

These dry-land feeding fields can become magnets for late-season greenheads, particularly when the birds key on cornfields as the snow cover increases.

For such land-based hunting, Renner said, a good spread often consists of a 100 or so Canada goose decoys -- a spread that mallards will typically decoy into very well. Still, it never hurts to add a dozen or two mallard shells to a goose decoy spread, to increase the odds for a late-season limit of dry-land ducks.

THE DEVIL IN THE DETAILS
How about calling? With the possible exception of field-hunting for geese and ducks, Renner said, less calling action can be "more."

"I would say that location is more important than calling is, unless you have a day of fog or limited visibility," he said. "Then calling becomes extremely important. But most (late-season) days, it seems like laying off of the call is (one of) the best things you can do."

One thing hunters should not lay off of is big shot sizes in their non-toxic waterfowl loads.

Because most late-season duck-hunting shots are up-close and personal, Renner said that he'll typically use 3-inch steel loads in No. 2 or 3 shot sizes fired through a modified choke.

When goose hunting -- remember, geese are also a surprise possibility on most river duck hunts -- the DU biologist likes to shoot loads of BBs.

Layout style blinds are great for field hunts for mallards and Canada geese, but when hunting around the rivers, Renner said, he likes to rely on available natural cover to hide his location. Cover can consist of weeds, cattails, brush, willow trees or the branches of a fallen cottonwood.

And don't forget that "the devil is in the camouflage details." Match your camo to your surroundings, wear gloves and a facemask, and pick up empty hulls and trash that can spook late-season waterfowl that are flying overhead.