Bird at church has a couple of fellows chin-wagging (9)
I believe the answer is:
chaffinch
'bird' is the definition.
(chaffinch is a kind of bird)
'church has a couple of fellows chin-wagging' is the wordplay.
'church' becomes 'ch' (abbreviation on maps etc).
'has' is a charade indicator (letters next to each other).
'couple of' shows that letters should be duplicated.
'fellows' becomes 'f' (this could be a standard abbreviation I've not previously seen).
'wagging' indicates anagramming the letters (letters swing or wag around).
'f' duplicated is 'ff'.
'chin' with letters rearranged gives 'inch'.
'ch'+'a'+'ff'+'inch'='CHAFFINCH'
'at' is the link.
Can you help me to learn more?
(Other definitions for chaffinch that I've seen before include "Small European songbird" , "Common bird" , "Singer" , "flier" , "Garden bird" .)