About bird being yellow (6)
I believe the answer is:
craven
'yellow' is the definition.
(both can mean cowardly)
'about bird' is the wordplay.
'about' becomes 'c' (abbreviation for circa).
'bird' becomes 'raven' (raven is a kind of bird).
'c'+'raven'='CRAVEN'
'being' is the link.
(Other definitions for craven that I've seen before include "Contemptibly cowardly" , "Without backbone" , "Yellow" , "Faint-hearted" , "Mean-spirited" .)