Two ducks in New Forest getting tired (8)
I believe the answer is:
footsore
'tired' is the definition.
('footsore' can be similar in meaning to 'tired')
'two ducks in new forest' is the wordplay.
'two ducks' becomes 'oo'.
'in' indicates putting letters inside.
'new' indicates anagramming the letters.
'forest' with letters rearranged gives 'ftsore'.
'oo' put inside 'ftsore' is 'FOOTSORE'.
'getting' acts as a link.
(Other definitions for footsore that I've seen before include "Tired from walking" , "Suffering from much walking" , "Maybe needing plaster" , "Feeling effect of too much walking - put on slippers" .)