For a band so widely recognized as being wild-eyed experimentalists, Mercury Rev have refined their songwriting down to a definite formula. Ever since 1998s enchanting Deserters Songs, it's been swirling, sugary melodies, insistent rhythms, and Jonathan Donohues childlike voice amid trippy atmospherics. The Secret Migration doesnt stray from the formula; it refines it further. Guitarsonce the Revs chief weaponplay a supporting role here. A piano sways forlornly around a nearly danceable beat on Vermillion; the Phil Spectorish In a Funny Way works strings, woodwinds, dive-bombing guitar, twinkling glockenspiel, and the haunting whirr of a Theremin into a woozy wall of sound. But the songs are surprisingly tight. At the moment you might expect the band to descend into a noodley bridge, it often draws songs to a close instead. Fans of 12-minute epics about ancient mariners or the autumnal equinox will be bummed, but the rest of us who hate Phish are psyched.