Lark that is hiding around dicky bird (12)
I believe the answer is:
capercaillie
'bird' is the definition.
(capercaillie is a kind of bird)
'lark that is hiding around dicky' is the wordplay.
'lark' becomes 'caper' (I've seen this before).
'that is' becomes 'ie' (abbreviation for id est, 'that is' in Latin).
'hiding' indicates putting letters inside.
'around dicky' becomes 'caill' (I am not sure about this - if you are sure you should believe this answer much more).
'caper'+'ie'='caperie'
'caperie' placed around 'caill' is 'CAPERCAILLIE'.
Can you help me to learn more?
(Other definitions for capercaillie that I've seen before include "Bird" , "Type of northern grouse" , "Large grouse; a paler icicle (anag.)" .)