A McLean builder, Miller and Smith, announced plans yesterday to construct a community of 1,380 houses, a shopping center and recreation facilities on the 357-acre Claude Moore Conservation Education Center in Loudoun County.

The firm, which proposed to keep 17 acres as a nature preserve, bought the land, near Sterling in March for $8.5 million from the National Wildlife Federation over the objections of local residents who hoped it would remain undeveloped.

County Supervisor Betty Tatum, whose district includes the proposed development, said yesterday she "can't say yes and can't say no" to the plan, but is concerned about the amount of housing and commercial development that the developer proposes to build.

The property is one of the largest undeveloped parcels in eastern Loudoun. Moore, a 94-year-old physician, donated the land to the wildlife group in 1975 and still lives there. The wildlife group had scuttled a plan to sell the property two years earlier, partly because Moore had objected at the time.

Miller and Smith has applied to the county for planned residential zoning that would mean denser development than the present zoning of one house per acre. Company officials said they expect rezoning negotiations and approval to take at least a year. The county's master plan calls for the land to remain undeveloped.

Miller and Smith's plan calls for a self-contained development of 1,380 town houses and single-family houses, a town center with more than seven acres of shops and several public squares, and a 57-acre park that includes a pond, athletic fields and a 17-acre wildlife preserve. It will be named Lanesmoore.

Gordon Smith, president of Miller and Smith Holding Co., said his firm expects a certain amount of "give and take" on its proposal during talks with county officials.

As an incentive for quick action, the developer has offered to donate $1 million for a community center if the plans are approved within a year, he said. Miller and Smith and other developers would expect to put up most of the money to build the park and facilities, Smith said, and would expect the county to make a contribution, the amount of which is still undecided, a Miller and Smith spokesman said.

Smith said Moore was briefed on the developer's plan, and "he hasn't raised any serious objections." Moore could not be reached for comment. Moore can continue to stay in his house, and the developer said his house would be preserved after his death.

Tatum said she is pleased by the developer's plan to donate 57 acres for a park, but is concerned the proposal includes too much housing and commercial development and not enough road improvements to handle the increased traffic. The site is on Rte. 637, southwest of Rte. 7, and Tatum said Rte. 637, a winding, narrow road, would require major improvements.

When the wildlife federation sold the land, it said it expected to use the profits to set up a national conservation fund for endangered plant and animal species.