The flier left after a meal (4)
I believe the answer is:
teal
'the flier' is the definition.
(teal is a kind of birdanimal)
'left after a meal' is the wordplay.
'left' becomes 'L' (common abbreviation).
'after' says to put letters next to each other.
'a meal' becomes 'tea' (tea is a kind of meal).
'l' after 'tea' is 'TEAL'.
(Other definitions for teal that I've seen before include "Variety of duck" , "Strange tale of a duck" , "Duck - dark greenish-blue" , "bird" , "Raise (subject matter)" .)