Red List Category
for more information about the Red List categories and criteria
Justification of Red List category
This species is listed as Vulnerable because, although there have been rapid declines in the past, the improving status of the population and habitat, in particular following the successful eradication of the last introduced predators (Pacific rat) on Little Barrier Island (where by far the largest numbers breed), leading to an increase in fledging success from 5% to 70%. This key step in turning the fortunes of the species followed the earlier eradication of cats from Little Barrier Island in 1980, and Weka from Codfish Island in the early 1980s. Although tiny numbers still occur on Great Barrier Island it may have been effectively extinct as a reproductively viable population for several decades.
670000 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 - Nearctic - realm
Realm - Neotropical - realm
Realm - Oceanic - realm
IUCN Ecosystem -- Terrestrial biome
IUCN Ecosystem -- Marine biome