Minnesota duck hunters rode a roller coaster last week.

First came a state waterfowl survey that showed the state's breeding duck population index was 475,000, down 33 percent from last year and 36 percent below the 10-year average.

But the next day, federal officials reported the North American duck breeding population was estimated at a record 48.6 million, up 7 percent from 2011 and 43 percent above the long-term average.

So should hunters break out the champagne, or cry in their beer?

Possibly neither. The bottom line is Minnesota hunters could see a duck hunting season comparable to that of last fall, which by most accounts was decent.

But hold on to that hankerchief. Because despite the high duck numbers this spring, many experts fear that the continued and widespread loss of grasslands and wetlands in the prairie pothole region of the United States and Canada could mean this year's high breeding duck numbers are an aberration. North Dakota alone has lost 1 million acres of Conservation Reserve Program (CRP) grasslands since 2007, and it could lose another 1.7 million more by 2014. Minnesota has lost 300,000 acres since 2007 and could lose another 300,000 acres this year. And wetland drainage is accelerating in South Dakota.

"It does make you wonder if this could be a duck bubble,'' said Ryan Heiniger of Bismarck, N.D., a director of conservation programs for Ducks Unlimited. "As habitat goes away, the bubble could burst.''

Another reason to not get too excited about the record North American duck numbers: Those are breeding ducks. The numbers are high because wetlands were full last year, and nesting conditions -- and reproduction -- was excellent. But those ducks found much drier and poorer conditions when they returned this spring. Total pond counts for the U.S. and Canada were down 32 percent from 2011.

"We probably won't see the production we saw last year,'' said Steve Cordts, Minnesota Department of Natural Resources waterfowl biologist.

So fewer ducks are likely to fly south come fall.

"I would say we'll have a year similar to last year,'' Cordts said. State and federal duck harvest last fall hasn't been released yet, so it's uncertain how hunters fared.

10 million mallards

Still, the U.S. Fish and Wildlife Service's spring breeding duck survey was eye-opening. The 48.6 million breeding ducks are 43 percent above the long-term average dating to 1955. Mallard numbers hit 10.6 million, the highest since 1999. Blue-winged teal set a record at 9.2 million. Scaup numbers went up 21 percent to 5.2 million.

But they also counted 2.6 million fewer ponds, including many temporary and seasonal wetlands critical for duck production. Pond estimates for the Dakotas and Montana were down 49 percent from last year.

"If we get dry here and lose the wetlands and upland nesting cover, the U.S. prairies just won't be able to produce at the amazing levels we have seen since the mid-1990s,'' said John Devney of Delta Waterfowl. "That will have a real impact on hunters almost everywhere.''

State ducks missing

Minnesota's survey showed the duck population index at 475,000, down 33 percent from last year and less than half the 1 million breeding duck goal in the DNR's Duck Recovery Plan.

The survey, designed specifically for mallards, estimates duck numbers for just a portion of the state. The breeding mallard population index was 225,000, similar to the long-term average of 226,000 but 21 percent lower than 2011 and 17 percent lower than the 10-year average.

See both surveys at startribune.com/outdoors.

Canada geese sky-high

Meanwhile, Minnesota's Canada goose population was estimated at 434,000, up from 370,000.

"I think it will be a banner goose year,'' Cordts said.

Doug Smith • dsmith@startribune.com; Twitter: @dougsmithstrib