Bird of prey is a high flyer (4)
I believe the answer is:
kite
I believe this is a double definition.
'bird of prey' is the first definition.
(kite is a kind of bird of prey)
'a high flyer' is the second definition.
(I've seen this in another clue)
'is' acts as a link.
(Other definitions for kite that I've seen before include "aeroplane" , "Toy that flies on end of string" , "Flying toy on a string" , "One's flown" , "Light frame toy held on a string - bird of prey" .)