Trails beginning to show rabbits (6)
I believe the answer is:
stalks
'trails' is the definition.
'beginning to show rabbits' is the wordplay.
'beginning to' says to take the initial letters.
'rabbits' becomes 'talks' (rabbit can mean to talk).
The first letter of 'show' is 's'.
's'+'talks'='STALKS'
(Other definitions for stalks that I've seen before include "Follows or tracks stealthily, game or victim" , "They support plants" , "Pursues stealthily, game or person" , "Follows stealthily with evil intent" , "Follows a prey stealthily" .)