One with leading role moved fast to trap a bird (9)
I believe the answer is:
spearhead
'one with leading role' is the definition.
(someone who leads a project)
'moved fast to trap a bird' is the wordplay.
'moved fast' becomes 'sped' (I've seen this before).
'to trap' is an insertion indicator.
'bird' becomes 'rhea' (rhea is a kind of bird).
'a'+'rhea'='arhea'
'sped' going around 'arhea' is 'SPEARHEAD'.
(Other definitions for spearhead that I've seen before include "Take charge of" , "Lead (a military attack)" , "Leading force in a military attack" , "those at the forefront" , "Take the lead in" .)