Grey-headed crow (7)
I believe the answer is:
jackdaw
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">grey-headed crow</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for jackdaw that I've seen before include "Small member of the crow family" , "Thief in Rheims" , "Small black crow" , "Grey-headed crow" , "Larcenous member of crow family" .)