Bird flu wigeon spread around area (6,4)
I believe the answer is:
guinea fowl
'bird' is the definition.
(guinea fowl is a kind of bird)
'flu wigeon spread around area' is the wordplay.
'spread' indicates anagramming the letters.
'around' indicates putting letters inside.
'area' becomes 'a' (maths abbreviation).
'flu'+'wigeon'='fluwigeon'
'fluwigeon' with letters rearranged gives 'guinefowl'.
'guinefowl' going around 'a' is 'GUINEA-FOWL'.
(Other definitions for guinea fowl that I've seen before include "African game bird" , "African bird related to the pheasant" .)