It’s a Christmas miracle. Every year, Erin “Ebird” Zindle, frontwoman of Ann Arbor folk group the Ragbirds, assembles a remarkable lineup of musicians to perform a wide variety of holiday-themed tunes. This year performers will arrive from as far away as Grand Rapids for a run of four shows at the Ark, December 7-9.

It’s no small feat to muster a small army of Michigan musicians (2016’s lineup numbered more than twenty-five players) for four consecutive performances. But the truly remarkable element of the show is the widespread collaboration among the players. Through careful arrangement and rehearsal, the show comes off as the product of a single, wildly talented ensemble rather than a series of individual spotlight numbers.

That collaborative spirit is apparent from the moment the entire cast assembles for an opening song. Especially in the intimate setting of the Ark, cramming the unwieldy group onstage seems itself to be a miracle. But musicians gamely share microphones, and the explosion of beautifully arranged harmonies is exhilarating. The 2016 show’s opening rendition of “O Come All Ye Faithful” was performed with a danceable African-inflected arrangement based on a rendition by the a cappella group Pentatonix.

From there, a small house band (last year composed of members of the Ragbirds, the Macpodz, and the Barbarossa Brothers) remains almost constantly onstage while other performers rotate on and off. The personnel changes can be cumbersome, but Zindle cleverly employs Ann Arbor comedian Shelly Smith as an emcee to bridge the gaps.

The musicians blend their talents beautifully, not only in the all-hands-on-deck numbers that open and close the show’s two sets but on almost every song. Besides the supergroup of local musicians that comprises the house band, there’s almost always an additional guest musician or two lending their talents to whichever performer is taking the lead on each song. Last year’s tunes ranged from a sly, jazzy take on Tchaikovsky’s “Dance of the Sugar Plum Fairy,” led by trumpeter Ross Huff and his horn section, to a playful “thrash-grass” rendition of “God Rest Ye Merry, Gentlemen,” with Native Howl singer-guitarist Alex Holycross channeling the raw energy of thrash metal on a mandolin.

In addition to reinterpretations of traditional Christmas songs, the 2016 show featured some unconventional picks, like Chris DuPont’s lovely rendition of Jackson Browne’s “The Rebel Jesus” and Crane Wives vocalists Emilee Petersmark and Kate Pillsbury’s spine-tingling take on “Once Upon a December,” the theme from the 1997 animated film Anastasia. Ragbirds member TJ Zindle, Erin’s brother, lit the stage afire last year with his energetic and humorous original rocker “Christmas Time at the Music Shop,” which pokes fun at the general din and consumerist frenzy that occur in a guitar store during the holidays. Erin chose her moving tune “Christmas in a Box,” inspired by the 2016 death of the siblings’ elder brother. Further broadening the diversity of musical styles, Grand Rapids rapper Rick Chyme performed “Come Together,” an original hip-hop number that engaged the Ark’s traditionally folk music audience in raucous call-and-response vocals.

The Ebird and Friends Holiday Show feels like an annual family reunion for southern Michigan’s music community. But the most important and tangible element of holiday spirit that comes out of this production is the sense of pure joy. Hearing this chorus of beautiful voices and instruments, displaying their individual talents and exuberantly coming together, it’s impossible not to feel what is often called the “Christmas spirit.”