Red List Category
for more information about the Red List categories and criteria
Justification of Red List category
This species is listed as Critically Endangered because, subsequent to serious declines since the 1800s, it underwent a population crash following rat invasions in 1990-2000, and it now has a very small population that has declined during the last decade. However, the global population is now increasing owing to successful translocations onto four predator-free islands, and control of predators in its South Island range, and if this trend continues it may qualify for downlisting once the number of mature individuals in the population is clarified.
50-249 mature individuals
Distribution size (breeding/resident):
Land-mass type - oceanic island - Oceanic islands are islands or island groups that are <200,000 sq km in size and separated from other land masses by >200 m sea depth. Generally Oceanic islands are islands or island groups that are <200,000 sq km in size and separated from other land masses by >200 m sea depth. Generally they have never been connected to a continental area by a land-ridge, and are volcanic in origin.
Realm - Oceanic - realm
IUCN Ecosystem -- Terrestrial biome