The bellydrugger comeback

After the END, thanks to the abundance of food and the lack of competition, bellydruggers rapidly expanded their range in both southern and northern forests.
Their radiation was however impacted by the arrival of rodents, which partially displaced on some occasions various bellydrugger species. Their overall diversity is still high, with more than 17 species (ex. insular forms) adapted to different fossorial environments, like the crested bellydrugger (Ornithoradix maritimus), a small yet majestic bird that possesses a small crest on the upper part of its beak, used to move away clay-rich sediments but also for ritual combats. 
They are mostly insectivorous and can be found in the highly productive soils facing the Ronne Gulf. Fibers and vitamines are integrated by feeding on roots and tubers, which are scratched with strong bites.

The most divergent bellydrugger is a nearly cosmopolitan species, which evolved a semiaquatic behavior: the riverdrugger (Ramphitalpa semiaquatica). It's probably the largest species of fossorial penguin and possesses wide and keratinized arms, which are helpful to dig up its den near riverbanks or swim swiftly in search of aquatic plants and invertebrates. They've practically re-evolved a similar ecology to their freshwater ancestors, icekissers, but with a more plant-based diet.
Unusually for a bellydrugger, riverdruggers can stand on their hind legs and awkwardly walk by leaning on both toes and the tarsus, like a plantigrade. The erect position is mostly kept while sun-basking after a long swim since this species does not possess water-proof feathers.  The erect position is also helpful for spot predators: when threatened, this bird can escape by jumping into water or its dens.
Like all bellydruggers,  riverdruggers can lay from 1 to 4 eggs that are then inserted in a special external pouch between their feet: in this particular species, the pouch can close hermetically, isolating eggs/chicks from water while swimming.