Terrariders
From skyscrapers to torpedos

The increase in open habitats has greatly benefited terrariders, a group of rostrids that rely on speed for their efficiency. While not as biodiverse as brumbles, they boast a nearly cosmopolitan distribution and are among the most abundant megafauna in Antarctica.

The easiest species to observe is definitely the immense terrarider (Struthiocollis invernalis), both for its exceptional size (over 150 kg in weight and nearly 3 meters in height) and for its large range, which extends from the limits of the Reliquia forest to the Lands of Wilkes.
Physiologically similar to an ostrich, the immense terrarider can be distinguished by its longer and more robust legs, which it uses to move better in deep snow and defend itself from predators. A well-placed kick is enough to send even the largest Antarctic carnivores to their demise, who usually prefer to hunt less challenging herbivores. If given the opportunity, terrariders can also sprint at incredible speeds to escape from predators. In order to support their weight on the snow, they possess a skin membrane between their only two digits, which increases the surface area for support.
Due to their stature and flexible necks, terrariders are large generalist herbivores that can feed both on the ground and on tree branches. Unlike brumbles, they do not crush food with false teeth, but directly ingest and grind it inside the crop using gastrolites, like the majority of holocenic herbivorous birds

Like all post-lentocenic rostrids, terrariders have a type of wing pouch where they brood eggs and their young. Thanks to this evolutionary novelty, analogous to that of eggpouchers and bellydruggers, these species are able to protect their eggs and young from the cold and predators. However, this also implies a limit to the species' fecundity, as they cannot brood more than 4 eggs per breeding couple. Terrariders and other rostrids overcome this problem in various ways, including living in large herds that share surplus eggs with non-brooding members of the group, or prolonging parental care, which reduces chick mortality.

While the immense terrarider dominates the steppe environments of the continental areas, another species has decided to call the western coasts of the Antarctic Peninsula home, in the Infinite Archipelago, which now comprises fewer but larger islands. It is the islandhopper (Struthiocollis maritimus), a plump bird with amphibious habits. It has large webbed feet (larger than its continental relative) and relatively short legs, which make it an excellent swimmer.
Despite these characteristics, however, islandhoppers spend much more time on the ground, where they also feed.
The species evolved by reaching the archipelago a few million years ago, which greatly increased its size thanks to the receding seas. The stretches of water between one island and another are now very small, allowing islandhoppers to swim from island to island to find new foraging sites. The archipelago has proved to be extremely hospitable for islandhoppers due to its relative isolation from the mainland, preventing the continuous presence of large predators. For this reason, this terrarider dominates this island-like ecosystem, reaching almost exceptional densities for a technically insular species.
This rostrid bird moves in flocks of thousands of individuals, destroying every plant they encounter before moving elsewhere. This irregular migratory behavior makes this bird very adaptable but also favors other predators, such as marine ones. Aquashifts, large marine reptiles, are always lying in ambush, waiting for a herd of islandhoppers to pass