Reportedly spear seabird (4)
I believe the answer is:
skua
'seabird' is the definition.
(type of seabird)
'reportedly spear' is the wordplay.
'reportedly' shows a homophone (sound like).
'spear' becomes 'skewer' (skewer can mean to spear or pierce).
'skewer' sounds like 'SKUA'.
(Other definitions for skua that I've seen before include "Brownish sea bird" , "Seabird; sounds like pin" , "One preying on gulls" , "Large sea bird" , "Craziness" .)