‘Tis the season when the green Guinness flows and the Wild Rovers procure the kind of set to match the liquid meal: Celtic, multi-layered and strong, their songs—like the drink—will put you in a dizzying spin of pub-friendly sing-alongs. And that’s why they’re the busiest band in Santa Cruz during St. Patrick’s Day. With six shows in town during the next two weeks, the Wild Rovers have been called to arms for an annual musical onslaught that starts this Wednesday opening for the Young Dubliners and culminates in a headlining show at the Catalyst Atrium on the day itself, Wednesday, March 17 (with stints at the Boardwalk, Poet & Patriot, and the Crow’s Nest in between). This, perhaps, surprises no one more than the band itself. After all, before forming in 2004, none of the members had any previous experience with Celtic music.