Two things you don't often see at the Minnesota Zoo amphitheater lingered around the stage while Los Lobos performed there Wednesday night: small, slimy frogs who were numerous enough to evoke biblical references, and a not-so-small (although he has trimmed down a lot) country-rock legend who opened the show but stuck around till the end. Both seemed to egg on the headliners a little bit, resulting in one of the East Los Angeles rock veterans' most spirited performances at one of their favorite venues around the country.

The opener in question, Steve Earle, is himself a zoo regular and didn't take the warm-up slot lightly. Despite his own website's proclamation that it would be a solo performance, the Texan-turned-New Yorker brought his full band the Dukes with him for the sold-out show. That included violinist Eleanor Whitmore, who provided the sweet harmony vocals often sung by Earle's gifted wife Allison Moorer. Early on, they played "Waitin' on the Sky" and "Gulf of Mexico," two death-riddled highlights from last year's "I'll Never Get Out of This World Alive." Then they dug back into the more youthful oldies "My Old Friend the Blues," "Guitar Town," "Copperhead Road" and "I Feel Alright."

Earle saved his most topical tunes for end of the 75-minute set. "City of Immigrants" was accompanied by a speech about how minority populations get slammed "every time things get tough in this country." Said Earle, "It's a lie. It always has been." The crowd responded even more favorably --standing ovation! -- for "This City," an ode to New Orleans' post-Katrina resiliency, which he wrote for HBO's "Treme" (spoiler alert: He regretfully reported that he will no longer appear in the series because "my character got shot in the face"). "Revolution Starts Now" made for a rocking, call-to-arms benediction.

With their arsenal of guitars -- literally all shapes and sizes -- Los Lobos' set-up took a good half-hour, thus shortening their set to only about 70 minutes. Earle sat by the side of the stage the whole time but never joined in, perhaps limited by the zoo's 10:30 p.m. curfew. He and the rest of the audience marveled at the veteran pickers' acoustic prowess, brandished for the first half-hour in such classics as "La Pistola y el Corazón," "Sabor a Mi," and "Saint Behind the Glass." The latter was one of four songs plucked from "Kiko," which is getting an expanded 20th anniversary reissue next month, and rightfully so (I'd personally rank it one of the top 25 albums of the last 25 years). "Wicked Rain" resulted in the night's heaviest electric jam, and "Short Side of Nothing" was a rare treat. Another deep nugget dug up for the show was "Teresa," from their side project Los Super Seven.

"We'd like to thank the mosquitos for not eating us alive tonight," Cesar Rosas quipped toward the end. Coincidentally or not, he and Conrad Lozano both wound up having to step around the frogs that made their way onto the stage, just one of many weird occurrences the zoo continually serves up. The frogs probably won't get in the way for this weekend's BoDeans shows, though: All the female audience members who danced on stage to the Lobos' finale mash-up of "Not Fade Away" and "Bertha" must've pretty well stomped out the problem.