Bird, duck, appearing in list (7)
I believe the answer is:
rooster
'bird' is the definition.
(rooster is a kind of bird)
'duck appearing in list' is the wordplay.
'duck appearing' becomes 'o' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' is an insertion indicator.
'list' becomes 'roster' (roster is a kind of list).
'o' put within 'roster' is 'ROOSTER'.
Can you help me to learn more?
(Other definitions for rooster that I've seen before include "male with comb" , "one going to sleep" , "One crows" , "Domestic cock" , "Farmyard cock" .)