Wandering in pursuit of black bird (9)
I believe the answer is:
brambling
'bird' is the definition.
(brambling is a kind of bird)
'wandering in pursuit of black' is the wordplay.
I cannot really see how this works, but
'wandering' could be 'rambling' ('ramble' can be a synonym of 'wander') and 'rambling' is found within the answer.
'black' could be 'b' (abbreviation as in pencil hardness) and 'b' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for brambling that I've seen before include "bird" , "Type of finch" , "berries" .)