Flying threats
Raptors (falconids and accipitrids) are the most biodiverse predatory birds of Antarctica, followed by skeagles (raptistercorarids) and owls (strigids). Raptors rarely share their habitat with skeagles: while the first ones usually live in steppes or scrublands and nest on cliffs, skeagles are instead forest-dwellers, nesting on large trees. On the other hand, owls had a lesser success, being able to colonize only Weddell island and the Belgrano forest: the absence of circadian rhythms in most of the continent was a strong limiting factor for this group, causing a competitive exclusion.
The largest member of the falconid family is the windfeeder (Anatifalco velox), a giant falcon as large as an eagle that has specialized in feeding on small ducktails. With its extremely aerodynamic structure, windfeeders dive towards the ground at high speed, aiming at the head of their prey; victims are then killed with a lethal beak strike that damage is skullcap. If possible, the kill is moved away to avoid mobbing from geotters and herdstalkers.
Unlike windfeeder, the wandering incubo (Vulturaquila rupestris), an accipiterid related to the crowned incubo, mostly uses its strong legs to take down its prey. Way larger than a Haast eagle, this bird is capable of killing even young bullducks by clinging and injuring their hips and legs. They can also follow injured prey on their ground, thanks to the moderate cursorial structure of their legs; this adaptation is extremely helpful to these heavy birds for taking flight from the ground without needing cliffs to jump off.
Most wandering incubos are found in the Scrubring, the richest ecoregion of Antarctica from a biomass point of view; ducktails comprise the majority of its diet (>70%), followed by rotbills (>10%). Where large prey become scarce or forest cover is too much dense, wandering incubos can live at low densities, preying on ground tyrants and geotters.
Coose were once a common prey for incubos that lived in the Aurora Forest, but the progressive increase of canopy closure has caused in the past the complete disappearance of these birds of prey from this area.
Only recently, thanks to the bulldozer action of Mastodon bullducks, incubos were able to return to the Aurora Forest, now slowly falling apart.
With the expansion of woodlands, skeagles had risen from the ashes, reclaiming lots of their lost range, despite being limited to woodland environments. They compromise at least 5 species in Polarica, all adapted to different prey and a different degree of crown closure.
The largest member is the mainland skeagle (Charadriraptor vorax), definitely smaller than a windfeeder or an incubo but still very spectacular, being twice the size of a goshawk (up to 2 kg/4,4 lbs). They mostly hunt ground tyrants and flying birds like passerines and columbids, which are killed mostly with their large beak instead of their legs. Large anatids are out of their potential, despite some rare observations of hunting on rostrid chicks being documented.
Mainland skeagle is the only fairly social skeagle: pairs remain together for life and show some degree of pack hunting during the breeding season while hunting ground tyrants. The female, smaller than its partner, pushes careless prey toward the male, cornering it. This behavior is probably used for having prolonged food before egg incubation.