BY JENNIFER KELLY

Banjos, accordions, fiddles, string bass...both Bowerbirds and Megafaun make use of the most traditional of backwoods instruments. Both root their sounds in a kind of barefoot simplicity, but neither is content to leave it there, instead taking flights in free verse, free jazz and three- and four-part harmony. The Bowerbirds end up with a kind of gypsy melancholic indie rock, striated with spiritual awareness, while Megafaun bounds from sound to sound, now string-band righteous, now wildly experimental, now pure California pop.

Megafaun, if you haven't heard already, is the remaining three-fourths of DeYarmond Edison after Justin Vernon left to become Bon Iver a few years ago. More specifically, it is a pair of brothers, tall, bespectacled Phil Cook on guitar and banjo, substantial Brad Cook on various guitars and basses, plus the singing drummer Joe Westerlund.

Their new album Gather, Form, Fly, out on Home-Tapes this month, starts in a gentle swell of plucked guitars, a shimmer of bowed cymbals building in the back - and so does the show. A violinist, Jess Fox, on hand for only a couple of New England shows, weaves in sad, sweet swaths of sustained sound, and then the piece gathers momentum as it turns into "Kaufman's Lament," one of the band's new Byrds-ish forays into high pop harmonies. What is surprising about the song live, versus the record, is how hard even the softest songs rock, founded on hard, steady, four-four pounding, paced by rigorous banjo rhythms. "We had no choice, we had to try," the song ends, the players in a ghostly three part harmony, which fades into room tone and overtones.

Megafaun's set is mostly - maybe entirely - drawn from the new album, but even so remarkably diverse. There is the gloriously sunny pop of "The Fade" and "Guns," the Akron/Family-ish communal folk of "Worried Mind" and "Columns" (both songs led by drummer Westerlund), and the country frolic of "The Process." There is even a long descent into free-form experimentation in "Darkest Hour," all country elements receding into a mesh of found noises, proggy drones and extended instrumental jam.

In between the songs, Phil Cook seeks to engage the audience, asking them, at one point, if they've ever "gone through a phase", then confessing his own brief fascination with the outdoors, conducted mostly by studying camping catalogues. "Our father got kind of pissed with him, because he tried to set a controlled fire in the garage," Brad Cook explains. There is another bout of brotherly one-upping, when Phil Cook mentions that the violinist has made her own violin, "That's like making the car you drive. That's like building the house you live in." Brad Cook adds, "That's like inventing the language you speak in," but the drummer wins the round with, "That's like changing the diaper you just took a dump in." Yes, well, hard to top that.

Megafaun and Bowerbirds know each other pretty well, so when Brad Cook breaks a string mid-set, it is Bowerbirds singer and main songwriter Phil Moore who fixes it for him. Brad Cook plays string bass (and for a couple of songs, drums) in the Bowerbirds set, as he did in a recent European tour, and the two bands' members seem genuinely fond of each other.

Bowerbirds' two principals set up, Moore tuning guitars, accordionist Beth Tacular checking keyboards and mics and floating an instantly recognizable Appalachian flutter into the air. Mark Paulson, who plays violin and drums, sometimes simultaneously, borrows a chair from my table and hoists it up onto the stage. And Brad Cook wrestles a gleaming double bass up onto the stage, leaning it casually against the back wall.

Like Megafaun, Bowerbirds is working mostly new material, concentrating on songs from their second album Upper Air, which came out early in July on Dead Oceans. There are several older songs on the set list, "In Our Talons", "Hooves,", "My Oldest Memory," and "Dark Horse", which, among other things, demonstrate how much denser and more band-like the Bowerbirds' sound has become. Still the night's focus is on songs that must be still relatively unfamiliar to fans. The band plays seven of the ten songs from Upper Air.

Bowerbirds is more settled in its approach than Megafaun, finding a steady, mournful groove in the wheeze of accordion, the malleted pounding on a sideways bass drum, the jangle and slash of acoustic guitars. Perhaps "Beneath Your Tree" is more driving than other songs, perhaps "House of Diamonds" more contemplative and abstract, perhaps "Silver Clouds" has more of a folky simplicity, but they are all cut from the same basic cloth. All center on Moore's bright, capable tenor, making octave-high jumps with casual ease, sputtering quick bursts of poetry that outpace the songs' rhythms then slowing, building odd little crescendos into melodic lines and even individual notes, in a way that breaks up the melody into shreds and shards.

Tacula joins him at intervals, singing counterpoint in "Beneath Your Tree," in a soft country descant, or blending in close harmonies in "Chimes." She switches from accordion to keyboards to drums, during the course of the set. Still her accordion playing is one of the most memorable elements of the band's sound, warm and dense and bittersweet. And Paulson is a remarkable multi-tasker, spooling out wild ribbons of country fiddle as he pumps the drums with his feet.

The band ends their regular set with "Hymn for a Dark Horse," the title song from their debut, which is very fine, but somehow less substantial and arranged than the new material. You get the sense that they have come together a bit more in the two years since the first album, and developed a sound that is not just added onto to Moore's fleeting, evocative songs, but an integral part of it.

Then there is a short, rather strange interval, with the whole band huddled at the side of the stage (there's no real backstage at the Iron Horse, though, when it's not pouring down rain, you can go outside between the regular set and the encore). They come back for "Bright Future," one of the evening's loveliest moments, with Cook filling in the wide ellipses in the verse with jazz-tinged, late-night bass runs. They close and ask, somewhat hopefully, if anyone knows of any dance parties?

Not me, but if you're looking for some backwoods poetry, laced with melancholy, cracked with humor and free inquiry, you could do much worse than Bowerbirds and Megafaun.

 [Photos credit: Jennifer Kelly]