The imposing folk-roar of Espers has died to a hush, but Meg Baird has been keeping herself busy as a solo performer. A distant relative of song collector I.G. Green, Baird hews close to the airy sound of Fairport Convention’s Sandy Denny, with a touch of Appalachian lilt now and then. On her new LP, Seasons On Earth, her fluttering voice and nimble finger-picking lend themselves to songs of sorrow and loss, whether vintage murder ballads or original compositions that are virtually indistinguishable from their handed-down forebears. She does a heartbreaking version of Big Star’s “Thirteen,” too.