In November, long-standing Irish folk legends the Chieftains announced that they were recording with Bon Iver, the Decemberists, Pistol Annies and more for their new LP, Voice Of Ages. Last month, we heard Bon Iver's collaboration with the group, "Down In The Willow Garden," and now the Decemberists' contribution has surfaced at Rolling Stone, a cover of Bob Dylan's "When ...