Los Lobos remains one of America's best live bands and certainly one of the premiere purveyors of American music. However, the veteran East L.A. group's performance Sunday at the Minnesota Zoo was, frankly, one of their lesser of many efforts there.

Singer/guitarist David Hidalgo seemed to be having some kind of vocal problems. Or maybe the mosquitos were just bugging him too much. While singer/guitarist Cesar Rosas seemed to have fire in his belly, voice and guitar, Hidalgo had it only in his guitar work (loved his trippy, Jerry Garcia-like solo on Traffic's "40,000 Headmen" and several bluesy forays throughout the night).

His voice didn't sound at full strength and his spirit seemed lacking. His voice was so off on "Will the Wolf Survive" that one wondered if he'd survive the night.

Perhaps because of his vocal challenges, the band seemed to be calling audibles rather than relying on a prepared set list. Hidalgo would sing lead on a song, afterward Rosas would start and sing the next number, and so on.

Hidalgo had his vocal moments during the 100-minute set. The band really found the groove when Hidalgo tore into Fats Domino's classic old rocker "The Fat Man." Hidalgo found his comfort zone on the Grateful Dead's buoyant "Bertha," one of the night's highlights.

By contrast, Rosas was consistently compelling, most notably on "I Got To Let You Know," which sounded like old time rock 'n' roll fueled by accordion; "Maricela" with Steve Berlin's saxophone inducing some serious hip-swaying; the spunky power-pop "Set Me Free (Rosa Lee)"; and the rambunctious encore "Don't Worry Baby."