(Scott Johnson) Chris Hillman was a teenage bluegrass star on the Los Angeles music scene in the early '60s. A few years later, when Roger (then Jim) McGuinn asked him if he could play bass for the band he was forming, he said yes and then taught himself how. Moving from mandolin to bass he become one of the founding members of the Byrds together with McGuinn, David Crosby and Gene Clark.
Source: Power LinePower Line