UPPER AIR, the Bowerbirds' second release, finds the band continuing in the vein of their first effort; this is rustic, cerebral, ramshackle music. One could call it "beard rock"--it's the kind of backwoods, wild-poet-of-the-mountain sound that nods to Bon Iver, Bonny Prince Billy, and Iron & Wine. What makes the Bowerbirds just a touch different lies in how manipulative (in a good way) their songs can be. "House of Diamonds," with its stormy percussion and piano chords, and blocky guitar riffs, is simply electrifying. But the Bowerbirds really are at their best when they call up the quietly fiery side of their sound. "Ghost Life"'s wordless chorus (a series of triumphant "ohs") shouldn't be as convincingly uplifting as it is; it's a testament to the Bowerbirds' creative chemistry and pop sensibilities that it works as well as it does. 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, strangehearted stuff this disc has to offer