Like seabird at back of ship (6)
I believe the answer is:
astern
'back of ship' is the definition.
'astern' can be an answer for 'back' (I've seen this in another clue). I'm not certain of the 'of ship' bit.
'like seabird' is the wordplay.
'like' becomes 'as'.
'seabird' becomes 'tern' (tern is a kind of seabird).
'as'+'tern'='ASTERN'
'at' acts as a link.
Can you help me to learn more?
(Other definitions for astern that I've seen before include "The wake is" , "Towards a ship's rear" , "Towards the rear of boat" , "Rearward" , "at the vessel's rear" .)