Slush continues to plague Minnesota lakes, making travel difficult for anglers and others. The slush and water on the ice has made the lakes "miserable,'' reported conservation officer Dan Malinowski of Fosston. And in the Cook area, officer Brad Schultz reports very little ice fishing -- or snowmobiling -- is occurring because of snow and slush on the area lakes. Early snow insulated lakes, slowing ice formation and causing slush.

Conditions vary greatly around the state, and anglers are advised to use extra caution. Slush conditions have improved recently in the Grand Marais area.

Near Mora, there is 5 to 11 inches of ice with lots of slush. Near Perham, it's 10 to 14 inches of ice, with slush. A pickup went through ice on Rush Lake, and another went through ice of Wood Lake near Montevideo.

Officer Dan Starr of Tower said lack of good ice continues to be a major concern. Some bays have up to 17 inches, but other areas have only 5 inches, he reported. He recommended not driving on lakes. Things were better near Bemidji, where officer Stacey Sharp reported that ice conditions continue to improve with most area lakes at 12 inches or more. Full-sized vehicles were driving on the ice.

Meanwhile, anglers are finding some action. The walleye bite is holding steady on Lake of the Woods, and many were getting their limit of fish at Red Lake.

Lots of anglers have been fishing Lake Mille Lacs, with most finding some perch and walleyes, officers reported. Ice conditions vary, and there still are patches of slush on the lake. Closer to the Twin Cities, some nice walleyes and sunfish were being caught on Lake Minnetonka, but the bite has been inconsistent.

Ruffed grouse mystery

Minnesota's ruffed grouse season ends Tuesday, but the mystery of why there apparently were fewer birds in the woods this fall lingers.

Here's the latest theory:

"We suspect -- we don't know for sure -- that the main culprit was a really hard freeze last spring after the nesting season was well under way,'' said Dennis Simon, Department of Natural Resources wildlife management section chief.

The cold snap may have frozen grouse eggs laid early in the nesting season. Officials know it froze Canada goose eggs, reducing nesting success.

"We know we lost most of our Canada goose reproduction in the northern third of the state, and there's no reason to suspect we wouldn't have had similar problems with other ground-nesting birds like ruffed grouse,'' Simon said.

The ruffed grouse problem first drew attention in October, when the ratio of young ruffed grouse to mature birds bagged at the Ruffed Grouse Society's National Ruffed Grouse and Woodcock Hunt near Grand Rapids was the third lowest in the event's 26-year history.

Hunters shot just 3.97 immature birds per adult female, compared to 10.65 last year. The long-term average is 6.7. That means young birds from this year's hatch were missing.

Goose eggs frozen

The evidence is solid that the cold snap hurt Minnesota's Canada goose population. As part of a wildlife study, a graduate student had 80 goose nests under observation near Moorhead, "and the eggs in all 80 froze,'' said Steve Cordts, the DNR's waterfowl specialist.

The result: poor reproduction and fewer geese.

"I'm sure we saw it this fall in the lower number of geese around; there were very few young geese,'' Cordts said.

West Nile to blame?

Another theory in the ruffed grouse disappearance is West Nile Disease, which has killed various species in Minnesota. But no one knows why the disease, which has been here for several years, would have such an impact on ruffed grouse now.

"At first I was thinking West Nile was unlikely,'' said Mike Larson, DNR grouse specialist. "But people supposedly saw good-sized [grouse] broods up through July.''

The problem is no one has studied the disease's effects on ruffed grouse. And, of course, there were no dead birds to collect and test. Larson said he would like to test the impact of West Nile on grouse in a lab.