Old and new raptors

Skeagles, once the main flying predators of Antarctica, vanished after the END and so did other raptorial bird species. Antarctic eagles (Accipitriformes) also went extinct (and, maybe, globally), while few species of falcons were able to survive in Antarctica somehow. Owls disappeared from the continent, but they made their reappearance shortly after the catastrophe, simultaneously to a new predatory bird group: parstrikers (clade: Deinopsittacidae).
These extremely bulky and intelligent birds are nothing less than very derived carnivorous parrots that rapidly evolved from omnivorous species after the END. They are usually forest-dwellers, but there are some species adapted to grasslands and even marine environments. Pack hunting is observed in many species, like the wandering parstriker (Psittaraptor americanus), the largest known species present in Antarctica and also one of the first to arrive. They can hunt both rodents and large birds by gripping their back with their strong talons and then aiming for the neck or head, which are brutally slashed thanks to their bone-crushing bite. 

Wandering parstrikers thrive in coastal forests but not in open grassland, where the bulletfalcon (Rapidifalco ornithofagus), a giant raptor far related to kestrels, can be found; this predatory bird possesses very short but incredibly sturdy legs that are used as a primary weapon. Long-necked birds are the favorite food of this falcon: these prey are killed by crushing their head or neck after a skydive that can reach 120 km/h.
Despite being one of the largest birds of prey in Antarctica, bulletfalcons are often harassed by sheardogs after killing large prey. The food is rarely shared with strangers and bulletfalcons always try to defend tenaciously their kill. These birds, however, are virtually harmless on the ground against chetters or a mob of dusk sheardogs and they must often leave their prey.