Cornfield invader (4)
I believe the answer is:
crow
'cornfield invader' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for crow that I've seen before include "'As the - - flies'" , "Gloat" , "Make sounds of pleasure as a baby does - or a bird" , "Black bird; brag" , "Native American -- bird" .)