Complex sentence: The Ua Pou Monarch is now listed as "critically endangered (possibly extinct)" after the IOC removed the Double-banded Argus from its list of valid bird taxa in 2011 BirdLife International and the IUCN did so in 2012.
Split into simpler sentences: The Ua Pou Monarch is now listed as "critically endangered (possibly extinct)". After the IOC removed the Double-banded Argus from its list of valid bird taxa in 2011 BirdLife International and the IUCN did so in 2012.