A bird has to take evasive action (4)
I believe the answer is:
duck
I believe this is a double definition.
'a bird' is the first definition.
(I know that duck is a type of bird)
'to take evasive action' is the second definition.
(I've seen this in another clue)
'has' acts as a link.
(Other definitions for duck that I've seen before include "Water bird - get out of the way" , "Zero score; avoid" , "strong cloth" , "Shoveler, for example" , "sails material" .)