JAMESTOWN, N.D. (AP) _ A pop-up scarecrow and a snowplow-proof mailbox were just some of the gizmos displayed at the second-annual North Dakota Inventors Congress.

Peter Konzak of Devils Lake rummaged through the clutter of his briefcase and found a letter to prove his scarecrow has already earned him some attention.

''I am still invited to the Johnny Carson show. It is a standing invitation,'' the 66-year-old retired farmer said.

Forty inventors and manufacturers, most of them from North Dakota, showed off their gadgets and thingamajigs at the show, which ended Tuesday.

The hinged mailbox was devised by a Minot man after a neighbor complained about his mailbox getting knocked down by snowplows each winter.

Konzak's pride and joy stood at one side of his booth on the floor of the Jamestown Civic Center. It's a steel contraption wearing fluorescent work gloves that sports a dummy's head adorned with a cowboy hat. A battery and propane tank give it life.

In a sunflower field, the clumsy-looking ''pest-scaring device'' jumps up, twirls and whistles to keep blackbirds from feasting on the seeds, Konzak said Monday.

''All you need is one on 40 acres,'' he said. ''With the buzzer in here and all the stuff, it can pay for itself in one year.''

Since receiving a patent for his mechanical scarecrow in April 1986, Konzak has made about 30 of them and sold them all at about $500 apiece, he said.

But he said he hasn't made any money yet. ''I've just made my expenses. I put $20,000 into patenting this thing.''

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HONOLULU (AP) - When Guam Gov. Joseph F. Ada checked out of a Washington hotel earlier this week, the hotel declined to take a Guam government check for payment of room charges.

''The hotel management said it couldn't accept the check because Guam is a foreign country,'' Ada said Tuesday during a stop in Honolulu on the way home.

''We told them that Guam is a U.S. territory where America's day begins.''

Guam long has been an unincorporated U.S. territory in the western Pacific, about 3,800 miles west of Hawaii.

''They said they would give me credit because I was attending the National Governors Association meeting,'' he said. ''What the hotel didn't realize is that they will receive the same government check for payment.''

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FAIRFIELD, Conn. (AP) - The president of Connecticut's third-largest bank is trading his pin stripes for dancing tights to help promote corporate support of the arts.

David Carson, 53, president and chief executive officer of People's Bank in Bridgeport, will play the role of the Duke of Courland in the ballet ''Giselle,'' to be performed March 11-12 by the Connecticut Ballet Theater in Stamford.

The production also will feature Stephanie Saland, principal dancer with the New York City Ballet.

''The bank has supported the theater, but I think you can support the arts with not just money, but with your presence, too,'' said Carson.

The ballet was looking for ''a very regal type of person,'' and it decided to approach Carson, said Brett Raphael, the company's artistic director.

''It occurred to me that this was natural casting if possible, however far- fetched,'' Raphael said. ''It's not every day a corporate personality takes time out of his schedule to dabble in a very different art form.''

Said Carson, ''It appealed to my sense of humor, and if it helps give the ballet some recognition, that's great.''

Carson will do some mime and walk to music, rather than dance. But, he asked, ''When does walking in time become dancing?''