OAKLAND — The Decemberists are known for incorporating elaborate stories and historical references in their songs, as well as audience participation. But Thursday at the Fox Theater, singer-guitarist Colin Meloy announced that they did not want to repeat themselves and would instead try something new with “stuff they don’t normally play.” Remarkably, Meloy only forgot the lyrics once.

The Portland band, currently on its “The Shuffling Off to Ragnarök Summer Tour,” opened its set with “Carry It All” off of 2011’s The King is Dead. As drummer John Moen began the song, accompanied by Meloy on the harmonica, fans sang along to the Tom Petty.-esque tune. Fan favorite “Leslie Anne Levine,” off 2002’s Castaways and Cutouts, came next. The song featured Nate Query on upright bass and Jenny Conlee on organ. “Sleepless,” a beautiful folky rarity off the AIDS research benefit album Dark Was the Night, followed and was a welcome surprise. Meloy’s nasally somber vocals were unmistakable.

Upbeat indie folk and pop songs “Down by the Water” and “Make you Better” showed off the band’s tight musicianship. Meloy, Query and Chris Funk, all playing guitars, produced a crisp, lush sounds that meshed with their backing musicians.

The highlight of the night came when opener Olivia Chaney joined Meloy on stage. The two have started a side project band called Offa Rex, a collaboration on which Meloy and the English singer-instrumentalist Olivia Chaney put a  modern spin on traditional English folk songs. On “Blackleg Miner,” an anti-strike-breaking tune, Chaney added a layer of softness while Meloy sung about “killing the scabs.”

On “Flash Company,” Chaney’s vocals carried a haunting sadness as the Decemberists backed her on acoustic guitars.

On “Everything is Awful,” a song about the state of the union, Meloy spoke his mind about politics and Nazis, adding a line about “the white supremacist in the White House.” A call-and-response singalong continued with the folk song “Sons and Daughters.”

The band picked up the pace with songs from its prog-rock-opera album, The Hazards of Love. The musicians would keep up the tempo through the end of the show. On “The Queen’s Rebuke/The Crossing,” the guitar parts came together, morphing into a power jam. A backup singer shined on the track, her vocals powerful and raw. The track led directly into “Annan Water,” which spotlighted Moen’s drumming.

The Decemberists’ encore was the nearly 20-minute, five-part mini-epic of Irish folklore: “The Tain.” Conlee came alive as she sang and played the organ. This song demonstrated how the band is incorporating its many styles, from prog-rock to folk balladry, drone psychedelia and even carnival sounds.

During those 20 minutes the band managed to travel around the world in a kaleidoscope of music.

Olivia Chaney opened with a short set of her own folky, sad love songs. She described them as the exact opposite of The Decemberists. Chaney played a keyboard to complemen her haunting vocals. She brought out Query and Conlee on some of the tunes. Her cover of Ewan MacColl’s “The First Time Ever I Saw Your Face” was a minimalistic affair, with Conlee playing an accordion.

Follow writer Rachel Goodman at Twitter.com/xneverwherex and Instagram.com/xneverwherex.