Democrat Howard P. Smith and Republican H. Roger Zurn Jr. are waging a traditional, neighbor-to-neighbor campaign for the Sterling District seat on the Loudoun County Board of Supervisors.

The Nov. 6 special election will fill the seat for the final year of the four-year term of Alice Bird, an independent who resigned last year.

Smith, who was appointed to the seat last year, and Zurn agree that their contest has implications beyond the cozy confines of their district, which is wedged between Sterling Park Boulevard and the Fairfax County line.

The race may give political activists much to chew on as the county approaches the 1991 redistricting process; the entire Board of Supervisors is up for new four-year terms in November of next year. Yet the Smith and Zurn campaigns have a local flavor, with each man emphasizing what he believes he can do for eastern Loudoun.

Smith and Zurn are knocking on doors, enlisting the aid of volunteers and discussing Smith's record during the past year on local as well as countywide issues.

The two do not disagree sharply on basic issues, such as taxes, transportation and housing. Yet they have displayed marked differences in style and are projecting distinct messages as they try to sway the district's 4,066 registered voters.

"I'm concerned about managed growth in Loudoun County, with all of its ramifications," said Smith. He is stressing "the attraction of industry into Loudoun to reduce the impact of the individual tax rate, and education, particularly this year" because of state government cuts.

"I want to retain Loudoun County's tax bill as the lowest in the Washington area," said Smith, though neither he nor Zurn would rule out a slight rise in the real estate tax rate if the county faces a large deficit and property assessments flatten out.

Zurn said his primary message is that "I'm action-oriented. We have some very severe problems in the eastern end of the county," including the need to provide more activities for teenagers.

"The government tries to spend too much and tries to tax people too heavily," Zurn said. He said he would hold regular town meetings in his district if he is elected.

Smith, a retired cartographer, favors establishing parks and preserving open space and said he is "committed to affordable housing in the county to take care of entry-level professionals." He said he is more "attuned to the problems of the elderly" than is Zurn, and that he is proud to run on his voting record.

Zurn, who owns Loudoun Temporary Services and is a former chairman of the county's Affordable Housing Advisory Committee, said he has been active in local civic affairs far longer than has Smith and criticizes the incumbent for having voted to increase the size of the county staff.

"We've got to find alternative sources of revenue and cut government spending," said Zurn. He said positions can be eliminated from the county government's "bloated bureaucracy."

Countered Smith, "I feel that many of his goals are simply campaign promises."

The struggling economy may be a larger indicator of how the 1991 supervisor races will turn out than will this year's Sterling District contest, Smith said. To Zurn, the 1990 special election promises "an opportunity for the voters to decide on a course of action for the next few years" for the entire county.

Officials of both parties note that no Democrat has been elected to the Sterling District seat for a decade. The position pays $18,000 a year.

Political analysts looking to gauge the popularity of the current Board of Supervisors also will be looking at the results of a countywide referendum that will determine whether the board chairman will be elected at large, rather than selected by the supervisors from among their ranks, beginning with the fall 1991 elections.

Two other countywide referendums and several other questions also are on the Nov. 6 ballot.

Loudoun voters will be asked if they favor parimutuel betting in the county and if the county government may sell $11.3 million in bonds to finance expansion of the landfill. And they will be voting in four statewide referendums that propose amendments to the state Constitution.

The state amendments would authorize personal property tax relief for elderly or disabled persons, would let proceeds from illegal drug seizures be used to promote law enforcement and would permit the state and localities to issue pledge bonds for transportation projects.

Also on Nov. 6, Republican U.S. Sen. John W. Warner will be challenged by independent Nancy B. Spannaus, of Lovettsville, and GOP 10th District Rep. Frank R. Wolf will face Democrat N. MacKenzie Canter III and independents Lyndon H. LaRouche Jr. and Barbara S. Minnich. Minnich lives in Sterling.