The Claude Moore Conservation Education Center and Historic Farm in eastern Loudoun County is not, says resident naturalist Craig Tufts, an unusual piece of countryside.

In fact, Tufts describes it as "your typical Virginia Piedmont farmland," with about 600 different plants, 194 kinds of birds, 30 different mammals, 20 species of salamanders and lots of butterflys.

Even so, Tufts and others at the National Wildlife Federation, which owns the land, are concerned, because they say the 360-acre farm near Sterling may be threatened by a shopping center proposed nearby. The farm even could be damaged to the point where the federation would have to sell it, they say.

Sunrise Development Corp., of Cleveland, is expected to file an application for rezoning in the next few weeks that would allow the company to build a 600,000-square-foot regional shopping mall on land opposite the Federation's conservation farm.

The Loudoun County Board of Supervisors is deciding whether to approve an amendment to the Eastern Loudoun Area Management Plan that would permit location of a regional shopping center on Rte. 7. Some county residents oppose the plan, suggesting that a shopping mall on the county's main commuter route would create a traffic nightmare like the one at Tysons Corner.

While there are three other companies vying for the right to build a shopping center in eastern Loudoun, county officials say they are attracted to the Sunrise proposal because Sunrise has offered to build a $1 million highway as part of the shopping center project.

"It's difficult to speculate about what kind of impact a shopping center would have, but there is a lot of opportunity for conflict," said Ron Way, vice president for public affairs with the Wildlife Federation. "It is something we would have to consider carefully."

One concern, Way said, is traffic impact. There is a little-traveled road running along the western border of the Federation's preserve today. Known as Rte. 637, it links Rte. 625 with Rte. 7 to the north and divides the Sunrise and Federation properties. The offer Sunrise made to the county Board three weeks ago is to build a new road just west of Rte. 637, running parallel to it, merging at a point just south of the Federation's land.

But Sunrise also offered to consider other options, including linking the shopping center access road with Rte. 637 at a point much closer to Rte. 7, which would bring traffic rumbling right past the bluebird boxes on the Federation preserve.

The county is expected to make a decision within a month.

"We know it's going to be suburbia out here before long, and what we wanted was to make this land a national model for managing wildlife in that suburban environment," said Tufts. "But the closer a four-lane road comes to the property the more it will impair what we are trying to do here."

If the Sunrise proposal ultimately gets approved by the county board, it could also force out the residents of Nokesville, a long-established, close-knit community of modest homes along Rte. 637.

"This is the first I've heard of it," said Edna Thornton, a 72-year-old woman who has lived there for 38 years. "I suspected there was something going on but I didn't think it was something like this. I don't think I would like a shopping center in my backyard."

Thornton's concerns were echoed by Mary Glenn, her neighbor of 25 years, who said her real estate taxes had already gone up. James Jeffries, minister of the First Baptist Church on Rte. 637, said the community would protest the proposed shopping center if it meant moving the church.

The Wildlife Federation is expected to vote on what to do with the refuge at its annual meeting this summer. Tufts said alternatives for the land range from establishing a conservation training camp for teachers, to selling the land for a housing development. The land is worth between $3.5 and $5.5 million and Tufts said the board of trustees might choose to sell it so that they could invest in more special property somewhere else.

If that is what they decide to do, the only place left in eastern Loudoun for native wildlife would be the Algonkian Regional Park north of Rte. 7 on the banks of the Potomac, a park with heavy recreational use.

Tufts sighted the first American bald eagle to be seen on the Federation's property last week--not nesting, just passing through--and later, while watching a pair of American kestrels building a nest, he explained that many of the birds come back year after year to raise their young on the property.

"It just makes you wonder where they go when the bulldozers come," he said.