WASHINGTON (AP) _ An acrylic painting by a 25-year-old Minnesota wildlife artist of two black-bellied whistling ducks was selected Tuesday to be used for the next Duck Stamp, covering the 1990-91 hunting season.

The award brings prestige and financial reward to the artist, Jim Hautman of Plymouth, Minn., who could earn as much as $1 million from commercial printings and other royalties, although the government pays no money for use of the painting.

Five judges selected Hautman, who had entered the Duck Stamp competition four previous times, after they sifted through 603 entries during two days of judging at the Interior Department's auditorium.

Well over a million of the stamps with Hautman's design will be sold for the 1990-91 waterfowl hunting season, bringing $12.50 apiece to the government. Last year the Interior Department received more than $13 million from the sale of the stamps.

Although the government sold nearly 1.4 million stamps last year, the demand for the stamps has been declining in recent years. About 2.4 million stamps were sold yearly in the early 1970s.

Norma Oprand, chief of the federal Duck Stamp program, attributes the decline to the reduction of the waterfowl population. With fewer ducks there are tighter restrictions on hunting and fewer hunters to buy stamps.

But the Duck Stamp, created in 1934 and produced every year since then, is much more than a source of federal revenue for the artist whose painting adorns the stamp.

''For the wildlife artist there's nothing greater than the Federal Duck Stamp,'' says Neal Anderson, the winner last year, who was selected in his sixth try with a painting of a pair of lesser scaup nestled amid a growth of reeds in a pond.

Barred like every other winner from competing for three years, Anderson observed this year's competition as the judges reduced the competitors to 26 entries on the first day and narrowed on a winner Tuesday.

Being selected for the Duck Stamp brings a wildlife artist instant recognition.

''You're one of a handful of people that have a piece of U.S. history,'' said Anderson.

And then there are the monetary rewards.

The government does not pay the artist a dime. But in recent years proceeds from the sale of prints have been lucrative, as have commissions from commercial use of the winning design on everything from T-shirts to commemorative plates.

''The artist himself should gross around $1 million or a million-plus,'' says Anderson.

The award transcends to the artist's other works as well, Anderson said, noting his other paintings sold more quickly and the value of his works in galleries rose 20 percent to 30 percent.

''You're not a better painter than the day before (you win). You're just more well-known,'' he said.