Upper Air, the Bowerbirds' second release, finds the band continuing in the vein of their first effort; this is rustic, cerebral, ramshackle music. You could call it beard rock -- it's the kind of backwoods, wild-poet-of-the-mountain sound that nods to Bon Iver, Bonnie "Prince" Billy, and Iron & Wine. What makes the Bowerbirds just a touch different lies in how manipulative their songs can be, which is just to say that there are times when Upper Air is exhilarating. "House of Diamonds," what with its stormy percussion and piano chords, and its blocky guitar riffs (so carefully amplified, it almost sounds like frontman Phil Moore is punching the strings), is, in its twine-rough, woodsy way, simply electrifying. Moments like this make it clear that the Bowerbirds are able to capture that certain, heart-snagging something -- it's the kind of thing that brings to mind Arcade Fire's best moments. The Bowerbirds really are at their best when they call up this quietly fiery side of their sound. "Ghost Life"'s wordless chorus (a series of triumphant oh's) shouldn't be as convincingly uplifting as it is -- but it is, and it's a testament to the Bowerbirds' creative chemistry and pop sensibilities. Upper Air only runs into trouble when the Bowerbirds get a little too introspective; some of the slow, meandering tracks here tend to get muddily dirge-like ("Chimes"). But this is a small issue in the wake of all the twisting, strange-hearted stuff this disc has to offer. Those who weren't so sure about the Bowerbirds before might change their tune with this release -- Upper Air is a luminous, wild-eyed affair, and a solid second album to boot.