Wedducks
Insular "ducks" of Weddell

Thanks to its northern position and not frosty sea currents, Weddell island is the most liveable territory of Antarctica. From cool austral forests to barren mountain tundra, its biomes are extremely variable. It should not surprise that Weddell is home to a unique and diverse genus of ducks, called wedducks (Archipelaganas sp.) (Family: Pelaganatidae).
They are very distant cousins of the duck clade of Polarica, independently losing flight and evolving in complete isolation for more than 25 million years. With their enormous feet and toothless beaks, they have lost most of their ancestral duck traits. To the untrained eye, they would look more like a moa. Even their ecology is more analogous to a moa.
They are herbivorous birds that have occupied most of the available niches: this has given birth to a moltitude of subgenera and species, adapted to different types of habitat. Small and stocky species (<20 kg/44 lbs) are typically found in mountain tundra and shrublands, like the Una Peaks Wedduck (Archipelaganas (Monticula) settentrionalis) of the northern part of the Antarctandes and the Hope Wedduck (Archipelaganas (Monticula) meridionalis) of the southern portion. Three woodland species of variable size are known from Weddell lowlands, while another species is found in steep woodlands, a small but increasing biome that will give birth in the next millions of years to the Vertical Forests of Weddell.
One wedduck was even able to colonize the near Ellsworth island, thanks to a land bridge.
Unlike the ayayema, which lives on an extremely small island, Wedducks are not negatively impacted by their insular condition. Weddel-Ellsworth archipelago is so large (>400.000 km2/154.441 sq. miles) that it can be labeled as a small continent, a sort of cold Madagascar, with a very balanced trophic chain (unlike typical island ecosystems). An alien species is not enough to take them down.