More students than usual transferred from private schools to the Highland Park school system this year, in what may be a sign of belt-tightening in the Park Cities.

School officials say they have no other explanation for the surge in new students during the first six weeks of the school year.

“It’s the economy,’’ said Highland Park school trustee Doug Smellage.

Overall, HPISD enrollment grew by 2 percent this year, in a district with about 6,400 students. Officials say some year-to-year variation is normal, but the largest increase is usually at the high school level.

This year, that was not the case.

“We saw more students than usual coming in from fifth through eighth," said Superintendent Dawson Orr.

At McCulloch Intermediate School, officials enrolled 67 new students this year. Most of them — 61 students — attended a Dallas private school last year, Orr said. That compares with 32 transfers from private schools at McCulloch last year.

Tuition at some of the area’s top private schools — The Hockaday School, St. Mark’s School of Texas and Episcopal School of Dallas — ranges from $20,000 to $24,000 this year for students in middle and upper grades.

Private schools have typically attracted about 20 percent of the students who live in the Park Cities, according to a demographic study conducted for the school district several years ago.

With the average home in Highland Park valued at around $1 million, some families have enough wealth to send their children to private schools, even when they live in one of Texas’ top-ranked districts.

Highland Park ISD, which also serves students who live in University Park, is rated exemplary by Texas officials.

The district’s lone high school is often among the top ranked in the country, and 98 percent of its graduates attend college.

The school district is in the midst of a renovation and expansion this year, because the aging campuses have not kept pace with the constant demand for good schools in a close-in neighborhood.

Voters overwhelmingly approved a $75.4 million bond campaign in May 2008.

Highland Park officials say they’ve been able to absorb the extra students this year without major disruption.

"The good news is we didn’t have to adjust staffing levels," Orr said.

The district has sought waivers from state regulators for some classes that exceeded state-mandated teacher-to-student ratios. But some waivers would have been needed anyway because the campus expansions were not complete when the school year began.

As for private schools, some admissions officials say they are not losing students.

“St. Mark’s opened the 2009-2010 school year with the highest enrollment in school history," according to David Baker, director of admission and financial aid at St. Mark’s. “For the year, we experienced very high retention and received more applications for admission than in any previous year."