The passerine dominance

After the END, many families of birds disappeared from Antarctica and have never returned. We don't know if these bird groups went completely extinct or were just incapable of reaching Antarctica again. Eagles (Accipitriformes) for example are mysteriously absent and so are gamefowls and woodpeckers. 

One group however has maintained its high diversity, despite the heavy species loss: passerines. A lot of new perching bird species have arrived since the END, with an even greater ecological differentiation. Some of them are migratory, like the Wasp Bill* (Vespipasser migratoria), a specialized bee-eating sparrow that regularly reaches Antarctica in the good season. Another common migratory bird is the antit (Fortiparus formicaster), a tit descendant adapted to eat ants; like Wasp Bill, antits possess a very long beak but also a very long tongue used to catch ants inside their nest. They are hot temper animals and they are often seen while furiously attacking clamorscutes, which may also feed on these insects. 

In coastal habitats wetland robins (Limnipasser longipes) become the dominant passerine during summer: while maintaining a migratory habit, part of its global population often does not leave Antarctica during the cold season, overwintering in subtropical environments. Other passerine species do not migrate at all, like the terrestrial wagtail (Gallimotacilla nigra), a derived motacillid that has become hyperterrestrial; they can be found in open habitats, with three recognized subspecies, found in the mediterranean scrublands of the Ronne gulf, in the coldvanna of Wilkes and the alpine tundra of the Central Massif.  While being able to fly, this species prefers to run from predators and mainly forage by walking on the ground. Their nest is also not built on trees but in the tall grass or, if available, abandoned ground tyrants' dens.

*the name is always capitalized