Phil Moore and Beth Tacular, the couple at the heart of Bowerbirds, live together in a self-built eco-friendly house in a wood in North Carolina. This snippet of biography more or less encapsulates their heartfelt modern folk music. The sparse percussion suggests the dry crackle of fallen twigs, Moore's wispy acoustic guitar replicates the shuffle of feet through autumn leaves, while Tacular's accordion whines like a wild midnight wind through shadowy branches. Moore's romantic lyrics wax arboreal, too: "I live in your tall trees, among your fearless leaves," he shivers in Bright Future. Yet, for all nature's influence, the duo's sound on their second album feels more contrived than organic. Upper Air does have its ethereal moments; mostly, though, its earnestness keeps it prosaically earthbound.