Cry of an owl, possibly? (3)
I believe the answer is:
low
'cry' is the definition.
(thesaurus)
'an owl possibly?' is the wordplay.
'possibly?' is an anagram indicator (I've seen 'possibly' mean this).
'owl' is an anagram of 'LOW'.
'of' acts as a link.
(Other definitions for low that I've seen before include "Depressed or base" , "Depressed; moo" , "Depressed; near the ground" , "Not high - that's mean" , "Not high or loud" .)