This is called "mantling" a really bad habit for falconry birds to get into.
This Gos hawk belongs to a friend, and has serious "Issues" (No, the bird, not the friend ... Oh wait ... as you were
)
That's what happens when you try and imprint a BoP and don't know what you are doing
I've taken it for awhile to try and straighten it out at the Cobra boot camp for raptors
The aggression is slowly diminishing, but the food imprint screaming is taking awhile longer ...
Back to the theme, Mantling or
guarding, is a trait of BoP's to protect / camouflage a kill from aerial predators.
( there are 3 chicks under there)
Oh look a gob shot