Andrew Bird is a violin virtuoso steeped in early jazz and Celtic folk who announced himself as a top-shelf singer-songwriter with 2007's Armchair Apocrypha. Here, he takes another leap, fusing Armchair's emotive indie rock with the chamber-music experimentalism of his early recordings. "Masterswarm" mixes swirling strings with flamenco hand claps; "Effigy" stirs country fiddling and vocal harmonies into a gorgeous spaghetti-Western theme. But it's Bird's impressionistic lyrics that carry the emotional payload. "Nomenclature" is a sweet ballad that explodes unexpectedly. And on "Oh No," he pledges solidarity with "harmless sociopaths" alongside his trademark whistling, making dysfunction sound as romantic as roses.