Since her days collaborating with the late, great Gram Parsons, Emmylou Harris has been an increasingly ubiquitous presence on other performers' records. She's lent her ethereal harmonies to so many records that the question is no longer who Harris has worked with-- it's who she hasn't worked with. You'd think such omnipresence would grow tiresome for the listener at some point, but with Harris, it doesn't, probably because she's one of maybe two countrified female voices who give life to the "sings like an angel" cliché (the other, of course, is Alison Krauss). Even when she puts out a solo album, it's not really a solo album. To wit, her current release, All I Intended to Be, features Dolly Parton, Vince Gill, and the McGarrigle sisters (one of whom, Kate, birthed the Wainwright sibs), among others, chiming in. In her enduring selflessness, there can be little debate that Harris is alt-country's matron saint. Hence, her visit to the Zoo should have an air of royalty to it, amidst the picnic baskets, giraffes, and elephant dung.