Bird with judge in black coat, not far ahead (8)
I believe the answer is:
nightjar
'bird' is the definition.
(nightjar is a kind of bird)
'judge in black coat not far ahead' is the wordplay.
'judge' becomes 'J' (abbreviation for judge).
'in' is an insertion indicator.
'black coat' becomes 'tar' (I've seen this before).
'not far' becomes 'nigh' (I can't justify this - if you can you should give a lot more credence to this answer).
'ahead' is a charade indicator (letters next to each other) (some letters go in front of others).
'j' placed into 'tar' is 'tjar'.
'tjar' after 'nigh' is 'NIGHTJAR'.
'with' is the link.
Can you help me to learn more?
(Other definitions for nightjar that I've seen before include "Nocturnal bird related to the swift" , "Nocturnal bird with harsh cry" , "Winger" , "Noct. bird (of harsh cry)" , "flier" .)