Bird with gold finish on beak has disappeared (3)
I believe the answer is:
auk
'bird' is the definition.
(auk is a kind of bird)
'gold finish on beak has disappeared' is the wordplay.
I cannot quite understand how this works, but
'gold' could be 'au' (Au is the chemical symbol for gold) and 'au' is located in the answer.
A single letter 'k' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'with' is the link.
Can you help me to learn more?
(Other definitions for auk that I've seen before include "Black/white northern diver" , "Diving sea bird" , "Stocky diving bird" , "Short-winged seabird" , "Northern seabird with small narrow wings" .)