Rising of the shield hero

Rails were virtually eradicated from Antarctica, mostly after the rise of mesocarnivores happened at the start of the END. Flightless clades went completely extinct, with the sole exception of an already discussed group of armed rails: armadrails. 
While armadrails could easily withstand long periods without food during the END thanks to their low metabolism, their highly active and insectivorous relatives, hedgebacks, wouldn't endure the consequences of volcanic eruptions.
On the other hand, armadrails' incomplete ectothermy caused lots of trouble at surviving the polar winter: the sole survivor takes the name of Hero of the burnt shield (Electirallus lapilloides).
The species was able to survive with two disjunct populations in Amery Bay,  thanks to climate mitigation by the ocean. The smallest population was located in Pocket Islands and a larger one in Willowcoal Peninsula.
While the insular population couldn't expand its range and eventually became extinct after a slow and deadly vortex of extinction, the continental one slowly expanded its territory, colonizing the entire coastland of Amery Bay. Deriving from a relictual population of about 2000 individuals, well over the Minimum Viable Population (MVP), inbreeding issues seem to have not impacted much on this bird species.
Thanks to their great versatility and durability, armadrails have potential in the future of Antarctica, at least in the warmest regions..