The Mexican rock band Los Jaguares doesn't often use opening acts. The Jaguares' fan base is notoriously hard on whatever luckless band takes the stage as a warm-up act to their heroes.

On the surface, Eugene Rodriguez and his band Los Cenzontles looked like ripe fodder for the Jaguares crowd. After all, Los Cenzontles played corridos, rancheras and other song forms of Mexican tradition, not something this crowd would have much interest in. Imagine Pete Seeger opening for Nine Inch Nails.

But Rodriguez found himself and his band in the position of opening for Los Jaguares at the Fillmore in San Francisco. And he was more than a little wary.

"These kids were rock and rollers. They were not activists. They were not folklorists. They were rockers who identified more with Mexico than the United States."

So, Los Cenzontles -- "The Mockingbirds" -- took the stage with their folk instruments and their beautifully dressed female singers and sang what has turned into the group's signature song, the anthem from the 1970s titled "Soy Mexico Americano," an unapologetic cry of cultural pride of being a Latino in the United States.

"You just looked at their faces," said Rodriguez, the founder and leader of the band. "And you could see a transformation. You could see they were listening to something for the first time, which is really exciting for me."

Los Cenzontles comes to the Mello Center in Watsonville on Feb. 9 in a benefit for local folklorico dance troupes Sueños Aztecas and Esperanza del Valle.

Rodriguez, 50, was a kid during the fertile Chicano pride movement of the '70s, and had known the song for decades.

"That's all part of our history now. And to see it so powerful to this whole new wave of people who need to hear this message. I mean, they were yelling and cheering, just loving it. To see that song still relevant 40 years later, that to me was my favorite moment of playing that song."

"Soy Mexico Americano" was originally written by Texas singer/songwriter Rumel Fuentes as a contemporary ranchera in the activist period that spawned Cesar Chavez and the UFW labor movement. To Los Cenzontles, the song fits nicely alongside any number of old Mexican corridos in the public domain or mariachi ballads from the 19th century.

"We see tradition as a trajectory rather than a pinpoint in history," said Rodriguez, who serves as a guitarist, songwriter and producer with the band. "All traditions are always evolving. And we are custodians of that evolution."

Los Cenzontles comes to the Mello Center in Watsonville on Feb. 9 on the heels of a new album titled "Regeneration," which features contributions from a number of notables including Jackson Browne, Elvin Bishop, Pete Sears, Raul Malo and David Hidalgo of Los Lobos, a longtime friend and collaborator of the band.

"It's really a celebration of this new Latino generation that we are seeing," said Rodriguez of the new album. "Latino kids are the fastest growing demographic we have in this country. And although many people in our country are fearful of that fact, we wanted to create a document that was an embrace of that."

The new recording is less folksy and rootsy than past Cenzontles albums. That fact that the group is bringing in a more contemporary sound to go along with their deeply seated traditional sound is testament to Rodriguez's efforts to reflect the complexity and diversity of Mexican musical culture.

The band is the living embodiment of the Los Cenzontles Mexican Art Center in the North Bay community of San Pablo. Rodriguez serves as the director of the center and each of the band members are employees. At 50, Rodriguez is the oldest member of the group by far. In fact, Los Cenzontles consists of young people who grew up attending the center as children.

The band started in 1989, in a pre-Internet age when many musical traditions were threatened with extinction. Rodriguez, who grew up in Southern California, attended UC Santa Cruz and then got a master's in classical music from the San Francisco Conservatory of Music.

In the 1980s, Rodriguez was part of a widespread movement of young people interested in uncovering musical traditions that generations before them had deemed antiquated. "I remember in college," he said, "people would pass around cassettes of this band called Los Lobos, these young guys playing this old music with a lot of energy."

In 1989, Rodriguez started Los Cenzontles as a means to give context to the Mexican-American experience through music, to remind people of the vast cultural heritage of Mexican music.

The band, for instance, has been steeped for years in mariachi music, but it pushes beyond the popular conceptions of the horn-heavy bands playing in sombreros at Mexican restaurants.

"That modern mariachi style came of age in the 1930s and '40s and came out of big-budget movies of that period," said Rodriguez. "It's a lot like the cowboy music of the same era, the Roy Rogers thing, very stylized. And in Mexico, the old style was eclipsed."

It looked like the original mariachi style was dying out, said Rodriguez, until about a decade ago, he found an older musician who had learned the old style of mariachi music in rural Mexico, relatively unchanged from the mid 1800s. The new style, sans the horns and fancy outfits, is a string-heavy style designed for dancing.

"He taught us note by note, bowing by bowing, dance step by dance step, word by world this old style which is very different than we know today as mariachi."

At the Feb. 9 event, the group will perform some of that original mariachi music, sung in the language of the Purepecha, the indigenous people of the Michoacan region of Mexico.

Political activism is also part of the mix for Los Cenzontles but, said Rodriguez, a small part. Though the band is most concerned with reviving and re-energizing past Mexican traditions, they also speak out on issues, particularly in a political moment when the future of the United States is often couched in terms of growing Latino demographics. In that context, the group has in its set list the original song "Arizona: State of Shame," a protest song against the infamous Arizona anti-immigration law SB 1070.

"We played that song once at a school in front of a lot of Latino kids," said Rodriguez, "and one of the kids said afterwards, 'Dang, that takes some guts to say that out loud.' That's what happens in our community. We tend to sublimate our issues and our concerns. And it's time we got past that and stand up and speak out. What's right is right."

{ feb. 9 7 p.m.; Henry B. Mello Center for the Performing Arts, 250 E. Beach St., Watsonville; $12; a benefit for Sueños Aztecas and Esperanza del Valle; }