Bird displays dark container (8)
I believe the answer is:
nightjar
'bird' is the definition.
(nightjar is a kind of bird)
'dark container' is the wordplay.
'dark' becomes 'night' (it's dark at nighttime).
'container' becomes 'jar' (jar is a kind of container).
'night'+'jar'='NIGHTJAR'
'displays' is the link.
(Other definitions for nightjar that I've seen before include "Winger" , "Nocturnal bird related to the swift" , "Noct. bird (of harsh cry)" , "Nocturnal insect-eating bird" , "flier" .)