Just recently, the classically trained violin prodigy Andrew Bird underwent an abrupt musical transformation. Bird is still probably best known as a collaborator with the Squirrel Nut Zippers, and his two previous solo albums shared with the Zippers a fondness for pre-WW2 American popular music, from Stephen Foster’s post–Civil War plantation ballads up through ragtime and speakeasy-era “hot” jazz. But he seemed even less interested than the Zippers in music made after 1930; in interviews and on disc, he communicated a staunch and principled aversion to music made over the last 70 years. How then to explain the latest album credited to Andrew Bird’s Bowl of Fire, The Swimming Hour (Ryko) — a lush and rollicking ride through the orchestral pop, sweaty rhythm and blues, Appalachian fiddle romp, searing soul, and bombastic garage-band ruckus of the rock-and-roll era?

“I don’t know,” he admits over the phone from his Chicago home. “First, I stopped listening to records. Before I made this album, I had a kind of self-imposed bubble where I was trying to keep to a diet of strictly pre-war music, which I still love. I was pretty absent from listening to current music from about 1985 almost to the present. I was either immersed in the classical thing — playing violin concertos — or listening to whatever ethnic music I was into at the time; I had an appetite for anything non-Western. And that was all part of my education.”

Bird admits he’d grown weary of being lumped in with the swing revival. “There was the fear that we’d become a lifestyle band. I didn’t want to get caught completing someone’s fantasy of a different era. I feel we’ve previously been excluded from certain scenes where there’s smart music being made, because of certain associations. I was really excited before we started recording The Swimming Hour. I knew I had something different, I knew it felt more wholly creative, like there was more myself out there. The first two records were quality, but I was kinda hiding a little bit, dressing the songs up.”

For The Swimming Hour, he says, “we made a conscious effort to spend a lot of time and really produce this album well. But I feel like some of these songs happened almost as history did — like with little accidents. We’re playing more rock and roll now, but it happened because we went to New Orleans and then we went to Memphis. I don’t know what happened in Memphis, but some pop songs came out of it. I wanted to make a really good jukebox record, so the first things we did were the Booker T.–sounding stuff and the soul ballads. Then songs like ‘11:11’ and ‘Two Way Action,’ those are the ones I’m most proud of, because I don’t understand them. I don’t understand how those songs happened.”

The Swimming Hour’s lush, string-enhanced pop and authoritative blue-eyed soul has engendered a few comparisons to Nick Cave and Beck’s Odelay; thanks to Bird’s training in pre-war jazz, though, his evocations of ’50s rhythm and blues feel fresher and fuller than, say, the trash-compacted retro of the Jon Spencer Blues Explosion or Delta 72. And though he’s aware of how big a departure The Swimming Hour is from his last two albums, his intent, he says, hasn’t changed so dramatically.

“From my first record, I felt that — for where I was coming from — I was trying to write really effective, get-in-and-get-out pop songs. And for people who’ve grown up with pop music, that may not seem like the loftiest goal. But I didn’t grow up with pop music. And I’m fascinated with the whole idea of trying to come up with that incredibly effective song.”

He chuckles. “I mean, Lord knows I can be obscure.”

Andrew Bird’s Bowl of Fire play the Middle East, 480 Mass Ave in Central Square, this Friday. Call (617) 864-EAST.