Upset as deer are removed (6)
I believe the answer is:
erased
'are removed' is the definition.
(to erase is to remove or delete)
'upset as deer' is the wordplay.
'upset' indicates an anagram.
'as'+'deer'='asdeer'
'asdeer' anagrammed gives 'ERASED'.
(Other definitions for erased that I've seen before include "Removed by rubbing" , "Rubbed out, deleted" , "removed recording" , "Red sea (anag)" , "deleted material" .)