One leaves Moroccan port carrying a bird (7)
I believe the answer is:
tanager
'bird' is the definition.
(tanager is a kind of bird)
'one leaves moroccan port carrying a' is the wordplay.
'one' becomes 'i' (Roman numeral).
'leaves' suggests deleting specific letters.
'moroccan port' becomes 'tangier' (Tangier is a port in Morocco).
'carrying' is an insertion indicator.
'tangier' with 'i' taken out is 'tanger'.
'tanger' enclosing 'a' is 'TANAGER'.
(Other definitions for tanager that I've seen before include "American songbird" , "A bird" , "South American singer" , "Songbird of the bunting family" .)