The Mammals aren't the first band to mix an indie-rock sensibility with bluegrass sounds, but they're gradually becoming one of the best. On their fourth album, the New York-based band pushes against old-time templates with bright electric guitar figures, decidedly non-purist drums, bookish diction--principal songwriter Michael Merenda fancies rhymes like "façade," "barrage," and "Carthage"--and a sometimes poignant, sometimes pissed vision of life during wartime. "I'm Trying to Remember What City I Know You From" could be a Rilo Kiley song, with Ruth Ungar, in a dry but sexy voice, fumbling for a fan's name and wondering where they were when yet another war was declared. Political but never topical, the songs are empathetic when describing a woman left alone on a homestead with nothing but the bones of her family killed in battle, playful when asking, "If my guitar falls on a landmine, do you think that anyone hears?" And when the band succumbs to anger, they do so with a striking Spanish prayer sung by banjo-picker Tao Rodriguez-Seeger (Pete's grandson): "Solo le pido a Dios que la guerra no me sea indiferente" ("I only ask of God that I not become indifferent to war"). Given their indie sensibility, the Nirvana cover "Come as You Are" comes off as gratuitous; the country war-horse "Satisfied Mind," by contrast, reflects what's best about this album: its intelligence, discovery and conviction. --Roy Kasten