Rainfall and water levels on the big lakes are not the only factors that affect where and how we hunt ducks -- temperature can be important as well. Most of the time in Oklahoma, our big lakes don't have a lot of ice cover. Oh, maybe a bit of ice in the smaller coves, or within a foot or two of the shoreline -- but seeing acres and acres of ice cover on our big lakes is a rare thing.

But sometimes, especially later in the season, or when we get an unusually cold winter, ice locks up the best hunting spots. The shallower areas are usually the best duck-hunting spots, and shallower areas usually are the first to freeze.

That can be good or bad.

If the ice isn't too thick, you can break it up in pieces and slide the pieces either under or over the surrounding unbroken ice to create an opening for your decoys. If you have hundreds of acres of marshes covered in ice, then clearing a small area and spreading your decoys can be a magnet for ducks. Such work can be cold and miserable, but it can pay big dividends when you have ducks searching for open water.

Of course, if it remains cold enough for long enough, ice grows too thick to be broken and moved. Under those conditions, waterfowlers are forced to head for open water in the lower lakes, or to hunt around moving water that remains unfrozen.

An area featuring moving water is probably the kind of place least used by Oklahoma waterfowlers. I'm not talking about the main channels of rivers and creeks, but about those little pockets and coves and creek mouths kept open by moving water where currents are slowed or blocked significantly.

Several Oklahoma rivers are dammed repeatedly. The Neosho River (also known as the Grand River) is a good example. Up in the northeastern corner of the state is Grand Lake O' The Cherokees. Just below Grand Lake's Pensacola Dam is Lake Hudson, below which is Lake Fort Gibson. And a short distance below that, the Neosho meets the larger Arkansas River in the upper end of Webbers Falls Lake.

On the Arkansas River lie Kaw Lake, and then Keystone; then comes a long undammed stretch of river (a small dam in Tulsa that's only a few feet high excepted) until you reach Webbers Falls. From Webbers Falls Lake downstream, a succession of navigation lakes stretches to the Arkansas border.

These "chains" of lakes along major rivers can create stretches of open water even during very cold winters.

Most major dams are hydroelectric installations. As such, water is usually released from the dams for a certain amount of time daily. Those releases keep the downstream areas free of ice, or at least minimally frozen, throughout the winter. Sometimes those areas within a few miles below the dams are about the only open-water spots available to waterfowl and hunters.

Such areas don't have the room for thousands of hunters -- but, anyway, it's usually only the most determined shotgunners who go afield when the conditions are so tough.

Of course, if it remains cold enough for long enough, ice grows too thick to be broken and moved. Under those conditions, waterfowlers are forced to head for open water in the lower lakes, or to hunt around moving water that remains unfrozen.

I've seen ducks crowded into those open-water areas within a few miles below dams during really cold Oklahoma winters. I used to do a lot of midwinter striper fishing on the Lower Illinois River near its confluence with the Arkansas River. During really cold weather, when ice covers many areas, ducks descended on the little sloughs and eddies on the Lower Illinois because the flowing water released from Lake Tenkiller upstream kept those areas free of ice. You can find similar situations downstream from most major Oklahoma dams, or at least from those that generate hydroelectric power.