Remarkable bird swallows tail of bandicoot (9)
I believe the answer is:
startling
'remarkable' is the definition.
(I've seen this before)
'bird swallows tail of bandicoot' is the wordplay.
'bird' becomes 'starling' (I've seen this before).
'swallows' indicates putting letters inside.
'tail of bandicoot' becomes 't' (I can't explain this - if you can you should believe this answer much more).
'starling' placed around 't' is 'STARTLING'.
(Other definitions for startling that I've seen before include "Very surprising, astonishing" , "Surprising, shocking" , "Astonishing or shocking" , "Producing sudden alarm" , "Causing surprise" .)