By EMILY MITCHELL/Reported by Wendy Cole

They flocked together, the BYRDS of a feather, and in three days had cut four new songs. The threesome--from left, CHRIS HILLMAN, 47, ROGER MCGUINN, 48, and DAVID CROSBY, 49--reunited this summer for their first recording session in 18 years and made music so fast, McGuinn says, because "we've been at it longer and learned how to do it better." He once thought the group was history, but its 90-tune set of present and past work, which is out later this month, should be a boon for fans of the '60s--a decade, by the way, not missed by one wise old Byrd. Says McGuinn: "There was a lot of turmoil and drug abuse. I'm happier now."