Few but good
The tenacious herdstalkers

The slow but steady success of wardrums in the late Lentocene has strongly impacted herdstalker biodiversity, once being the main superpredators of Polarica.
Only two species have remained, both adapted to kill by using their beak like a hammer, a niche that wardrums were not able to exploit yet. However, they are far from being rare on the mainland: they are both generalist predators that were able to not only survive the wardrums’ diversification but even take advantage of it. 

The gracirunner (Gracilichionis continentalis) for example strongly benefited from wardrums’ kills and the reduced interspecific competition due to the disappearance of other herdstalkers: this small megachionid was limited in the past to temperate forests, while now it can be also found in less productive forests (like the austral forest) or open lands (like the Day-Night steppe).
When carrion are not available, the gracirunner feeds on cursorial ground tyrants, which are well widespread in the entire continent. This predator rapidly kills these large passerines with a rapid peck on their back, which usually causes lethal damage to the neural spine.
Due to their small size, gracirunners risk their life while stealing food from wardrums: this problem is partially solved by their long cursorial legs and their soft weight, which make these birds one of the fastest predators of Antarctica. 

While gracirunner has indirectly benefited from wardrums presence, another species has evolved a nearly symbiotic relationship with these carnivorous ducktails: the bravistalker (Anasphaganax funestus).
This large herdstalker is the most intelligent bird of Polarica, with neurological capabilities similar to a corvid.
They are far relatives of the shadowstalker: like them, they form packs, but in a completely different way. They live in fact in close contact with vojeagers, which not only tolerate these small predators but hunt and live together as well, forming a social group called gang.
Bravistalkers act like henchmen, stalking and pushing potential prey towards their ambushed chief, the vojaeger, which then will kill it.
This hunting strategy was firstly started around one million years ago by bravistalkers, which have slowly learned to communicate with larger wardrums to warn about the presence of large prey nearby and profit from their kill. This occasional commensalism behavior continued to improve over time becoming a bilateral symbiotic interaction. 

Both species have undergone a self-domestication process: vojaegers have become ambush predators, developing a graviportal structure, since they didn't need anymore to pursue their prey. Vojeagers' behavior has also changed, becoming more tolerant towards members of its species.
Bravistalkers have instead drastically increased their body mass and pack size, in order to scare larger ducktails: it's not rare to see groups of even 20 individuals mobbing large thronghorns, pushing them towards an ambushed vojaeger. Theirs youngs also possess a skull structure and coloration extremely similar to vojaegers' chicks: this anatomical feature has shown an increase in shared parental care between the two species, which ordinarily share their meal and shelter.

When a vojaeger becomes an adult and leaves its parents, part of the bravistalker pack breaks apart, forming a new gang. Bravistalker packs are however extremely dynamic, losing and adding new members periodically during the entire year, which helps to maintain a good genetic diversity.
Despite the complexity, this symbiotic relationship has turned these two birds into one of the most successful and dangerous predators that Antarctica has ever seen.