Follow bird on time (5)
I believe the answer is:
trail
'follow' is the definition.
(trail can mean to follow in secret)
'bird on time' is the wordplay.
'bird' becomes 'rail' (a wading bird).
'on' is a charade indicator (letters next to each other).
'time' becomes 't' (abbreviation).
'rail' after 't' is 'TRAIL'.
(Other definitions for trail that I've seen before include "Straggle" , "Rough track blazed through wild or hilly country" , "Mark left where something has passed - follow it" , "Beaten path; track" , "Be drawn belong behind" .)