After sunset, the container had a bird (8)
I believe the answer is:
nightjar
'a bird' is the definition.
(I know that nightjar is a type of caprimulgiform bird)
'after sunset the container' is the wordplay.
'after sunset' becomes 'night' (I've seen this in another clue).
'the container' becomes 'jar' (jar is a kind of container).
'night'+'jar'='NIGHTJAR'
'had' acts as a link.
(Other definitions for nightjar that I've seen before include "Nocturnal bird related to the swift" , "flier" , "Nocturnal bird of swift family" , "Noct. bird (of harsh cry)" , "Nocturnal insect-eating bird" .)