Blanched seeing that bird (5)
I believe the answer is:
ashen
'blanched' is the definition.
(I've seen this in another clue)
'seeing that bird' is the wordplay.
'seeing that' becomes 'as' (I've seen this in other clues).
'bird' becomes 'hen' (hen is a kind of bird).
'as'+'hen'='ASHEN'
(Other definitions for ashen that I've seen before include "Drained of colour" , "Like bird" , "pale in colour" , "(Of face) pale with fear" , "White-faced" .)