Wader's free paw poking fish (7)
I believe the answer is:
lapwing
'wader's' is the definition.
(lapwing is a kind of wader)
'free paw poking fish' is the wordplay.
'free' is an anagram indicator.
'poking' means one lot of letters goes inside another (poke can mean to create a hole in).
'fish' becomes 'ling' (ling is a kind of fish).
'paw' anagrammed gives 'apw'.
'apw' inserted within 'ling' is 'LAPWING'.
(Other definitions for lapwing that I've seen before include "Plover, pewit" , "Bird of the plover family" , "Flier" , "high-flier" , "Variety of plover" .)