Bird loses protective cover by half twice (8)
I believe the answer is:
caracara
'bird' is the definition.
(caracara is a kind of bird)
'half twice' is the wordplay.
'half' becomes 'cara' (I can't justify this - if you can you should give a lot more credence to this answer).
'twice' says to double the letters.
'cara' doubled is 'CARACARA'.
'loses protective cover by' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for caracara that I've seen before include "S. American bird of prey" , "New World bird of prey" .)