July 14, 1985

ABOUT a century ago, Eugene O. Wilcox came to Long Island from the Midwest. He settled in Speonk, among families including the Tuttles and the Hallocks, whose ancestors first touched the Island's shores in 1640. It was there that Mr. Wilcox first observed the ways of the White Pekin, a duck brought to Long Island from the Orient in 1873, and decided to go into the duck-raising business. His Tuttle and Hallock neighbors, who had been more involved in farming and fishing, quickly followed Mr. Wilcox into the new industry. Today, his farm, now called the Oceanic Duck Farm Inc., is still in operation. Its owner, David A. Wilcox, says that his grandfather's farm is the oldest continually operated commercial duck farm in North America. Also in operation are the Seatuck Farm Inc. of Eastport, owned by David W. Tuttle of the original Tuttle family, and the C & R Duck Farm Inc. of Westhampton, owned by John H. Phillips, a Hallock descendant.

A HOUSING-COST survey of 100 residential areas throughout the country has ranked the Monmouth County horse-farm township of Colts Neck as the second highest, just behind the Long Beach area of Los Angeles. In Colts Neck, the survey found, the average new home costs $225,000 and the average resale, $190,000; in Long Beach, the averages are $340,000 and $123,000, respectively. The survey was made by the Better Homes and Gardens Real Estate Service, a broker network based in Des Moines. It found that the average cost for a typical ''upscale'' home - 3 bedrooms, 1 1/2 to 2 baths, 1,600 square feet of living space and a ''desirable'' neighborhood - was $96,000 when the house was new and $83,000 for a resale. New Jersey real-estate experts say that Colts Neck prices are probably higher than the state average. The housing market, they note, is growing rapidly, with prices ranging from $5,000 for a row house in Camden to $4 million for a mansion in Saddle River.

The owner of Dubrow's Cafeteria on Seventh Avenue and 38th Street has agreed to sell his lease to a developer, apparently clearing the for the construction of a new building on the 20,000-square-foot site. Philip Pilevsky, president of Philips International Holding Company, a development company, said he has made a commitment to buy the lease, which will give him control of the site.

THIS fall, the Director Door Company of Copiague will move to new quarters more than twice the size of the 10,000-square-foot facility it now occupies. The company's vice president, James Director, said the expansion will mean adding 30 new people to his work force. The new $1.5 million plant, also in Copiague, is being built with low-interest, tax-exempt financing from an industrial development bond issued through the babylon Industrial Development Agency. ''We would not even have begun to start the project'' without the availability of the bond, Mr. Director said. ''We couldn't have afforded to do it.'' But the future of these bonds - the principal financing for much of Long Island's industrial expansion in recent years - is in jeopardy. President Reagan has proposed ending the tax exemption as part of his tax plan now before Congress.

ITS no-holds-barred advertising campaign for Prime Minister Margaret Thatcher created a national furor in 1979. Its 90-second sci-fi spot for British Airways - showing the entire island of Manhattan coming in for a landing at Heathrow Airport -was one of the most talked-about commercials of 1983. But in the past year, probably nothing that the Saatchi & Saatchi Company has done for its clients is as provocative as what it is doing on its own behalf. The huge advertising agency has been on a trans-Atlantic shopping spree, buying up not only advertising and public relations agencies, but even a management consulting firm. ''They're collectors,'' said Jeremy Bullmore, chairman of J. Walter Thompson's London agency, which Saatchi & Saatchi overtook in billings in 1979. ''They collect companies, clients, money, pictures, everything. They vastly enjoy growth and acquisition.''