Ducks seen in grassed avenues to the west (6)
I believe the answer is:
evades
'ducks' is the definition.
('evade' can be a synonym of 'duck')
'in grassed avenues to the west' is the wordplay.
'in' indicates the answer is hidden within the clue.
'to the west' says the letters should be written backwards (letters written right to left or 'east to west').
'sedave' is hidden within 'grassed avenues'.
'sedave' written backwards gives 'EVADES'.
'seen' acts as a link.
(Other definitions for evades that I've seen before include "Avoids by trickery" , "Manages to avoid" , "Dodges, steers clear of" , "Gets out of" , "Beats about the bush" .)