David Crosby passed away January 18, 2023, just two days ago.
He was a founding member of the Byrds (1964). He is on the far right in that picture, no moustache. 
Later, after he left the band in 1967, he got together with Steven Stills and Graham Nash to form Crosby Stills and Nash in 1968.
I remember listening to their tunes in the early 1970's.
He will be missed.
Hal