Tropical bird's gullet swallowing roughly (5)
I believe the answer is:
macaw
'tropical bird's' is the definition.
(I've seen this before)
'gullet swallowing roughly' is the wordplay.
'gullet' becomes 'maw' (I've seen this in another clue).
'swallowing' is an insertion indicator.
'roughly' becomes 'ca' (abbreviation for circa).
'maw' going around 'ca' is 'MACAW'.
(Other definitions for macaw that I've seen before include "Avian chatterbox" , "Tropical bird" , "Brightly-coloured parrot" , "Tropical parrot" , "Type of parrot" .)