There's no trash talk, no claims of supremacy — in fact, the school's director is a big fan of the St. Paul public schools.

But if you are looking for the story about enrollment growth in St. Paul today, it's not among the city schools, but at charter schools such as the St. Paul Conservatory for Performing Artists (SPCPA) — just across the street from City Hall.

There, every hour or so, the kids pour out of skyway-level classrooms, filling the halls of the Lowry Building with cries of "Hey, Caleb!" or "Anna!" Janice Rettman, longtime St. Paul and Ramsey County elected official, has been close witness to the Lowry's transformation. To her, she said, the energy — with all those students — feels like "hockey tournament time."

This year, the charter school added 64 students, an impressive gain but just one piece of a 945-student enrollment increase this fall at charter schools across the city, according to Joe Nathan, director of the Center for School Change. As of Oct. 1, charter school enrollment in St. Paul stood at 12,241, compared with 11,296 a year ago, he said.

As for the St. Paul School District, it is up 17 students, from 37,840 in 2012-13 to 37,857 as of Oct. 24, preliminary figures show.

Charter school growth has been fueled in part by construction projects that include SPCPA's $4 million renovation of the Lowry Building, a $12.6 million addition/renovation at Hmong College Prep Academy in the Como area and the relocation of the High School for Recording Arts to a new space in the Midway area.

But the biggest reason for the rise, in Nathan's view, is the increasing number of families looking for "distinctive, high-quality options" for students, a desire that has led them to abandon traditional classrooms for Montessori, International Baccalaureate (IB), expeditionary learning or performing arts programming, among other choices.

The Twin Cities German Immersion School moved into a former Catholic church and school this school year, adding 65 students, while Great River School, a Montessori school that offers IB classes, added two elementary sections.

The St. Paul School District, Nathan is quick to add, "is responding — and I give the district credit for responding."

This fall, the district added a Montessori middle school and is making arrangements to move Open World Learning Community (OWL), an expeditionary-learning success story, to the former Humboldt Middle School — in part to draw more students.

OWL parents, in a recent letter to district administrators, touted the school as a "compelling in-district alternative to innovative charter schools."

Academics, too

In 2005, SPCPA opened in the Landmark Center at Rice Park with 135 students. Now, it has 611, according to the Center for School Change. Eighty percent are girls.

Students come from about 40 school districts, and they spend 4½ hours a day on academics and three hours on the arts, including dance, theater, musical theater, instrumental music and the vocal arts, Director of School Callie Jacobs said.

About 15 percent of the students are from St. Paul, she said.

Four years ago, Eli Newell, 17, of St. Paul, and Sénait Judge-Yoakam, 17, of Minneapolis, both now seniors, began to make the trek between classrooms in the Landmark Center — affectionately referred to by students as "The Castle" or "Hogwarts" — and the Lowry Building, where SPCPA had been leasing space.

Newell, who is in theater, and Judge-Yoakam, who is in dance, found themselves at SPCPA in part because they couldn't land spots in the high schools they wanted in the St. Paul and Minneapolis districts.

They heard the jokes, endured the ribbing, they said, comments suggesting that SPCPA was all arts, no academics, and questions like: "Do you have a math class?" Newell said.

In 2013, 81 percent of SPCPA's 11th-graders tested proficient in math, compared with 52 percent statewide.

A couple of blocks away, the St. Paul School District operates Creative Arts High School, focusing on the literary, visual and performing arts. It has about 250 students, but is expected to grow to 600, said Steve Unowsky, the district's assistant superintendent of middle schools.

With 37,857 students overall, the St. Paul School District has shown an increase of 77 students since the 2010-11 school year, significantly below the 3,000-student increase that Superintendent Valeria Silva then set out to achieve over a three-year period.

Nathan, asked for the downside for the district as charter schools continue to grow, said: "The dollars for the kids. If the district had more kids, the district would have more resources."

At SPCPA, you'd need an electronic access card to get you far, but during a recent tour, Jacobs led a visitor past the second-floor science labs, the first-floor math classrooms and the black box theater, and into the basement where, back in Room B3, vocal department chairman Nathan Herfindahl, who at times sings the national anthem at Minnesota Wild games, led students through a section of Gilbert and Sullivan's "H.M.S. Pinafore."

"This is the last piece of the puzzle …" he said before they took a try at it.

This fall, all of SPCPA's classrooms are at the Lowry Building, and truth be told, Newell and Judge-Yoakam said, they miss the Landmark Center, despite the climb up four flights of stairs.

But they also see value in their newly renovated home.

"The new space, in a way, has validated us," Newell said. "We had a chip on our shoulder. There was a reputation of not being a 'real school.' Now we have a space that we can call solely 'our school.' It's a beautiful, unified school."

Anthony Lonetree • 651-925-5036