Justification of Red List Category
This species is classified as Endangered because its small population is estimated to be declining very rapidly, owing to the effects of introduced competitors and predators.
The population is estimated to be in the band 2,500-9,999 mature individuals in total, equating to 3,750-14,999 individuals, rounded here to 1,500-7,000 individuals. However, this estimate should be treated cautiously, as good data are only available from one population in the central North Island (T. Greene in litt. 2016).
This species is estimated to be undergoing a very rapid population decline (R. Hitchmough in litt. 2005).
Nestor meridionalis is endemic to New Zealand. The North Island subspecies septentrionalis survives in large forest tracts from Coromandel to Wairarapa, and is moderately common only in the forests of Pureora and Whirinaki and some offshore islands (Heather and Robertson 1997, Greene and Fraser 1998, T. Greene in litt. 1999). The South Island subspecies meridionalis is mostly found west of the Southern Alps, Fiordland and south-western Southland, Stewart Island and several offshore islands, and is in low numbers in all areas. The population is estimated at fewer than 10,000 birds (Heather and Robertson 1997), and new information indicates that the species has almost disappeared from the mainland except for a few intensely managed sites, and those valleys that remain free of possums and stoats. Three generations ago over 90% of the population would have been on the mainland, whereas now less than 50% is found there (R. Moorhouse per R. Hitchmough in litt. 2005). Mortality is highest in nesting females, so relatively large numbers of males can remain highly visible for a long time after the population reaches a very poor condition functionally (Greene & Fraser 1998, R. Hitchmough in litt. 2005).
This species inhabits large areas of low to mid-altitude forest. Its diet is diverse, consisting of fruit, seeds, nectar, sap, invertebrates (Beggs and Wilson 1991, Moorhouse 1997), and also honeydew in South Island Nothofagus beech forests (Beggs and Wilson 1991). It appears to depend on infrequently available, superabundant food crops in order to breed (Moorhouse 1997, Wilson et al. 1998, Greene et al. 2004, Powlesland et al. 2009). ). It nests in natural cavities in old or dying trees and usually lays four eggs (T. Greene in litt. 1999), with the chicks taking over seven months to become fully independent (Heather and Robertson 2015).
Historically, forest clearance and hunting decimated habitat and numbers (Heather and Robertson 1997, Moorhouse 1997, Greene and Fraser 1998, Wilson et al. 1998). Stoats Mustela erminea kill adults, in particular females incubating eggs, probably causing the highly skewed sex ratio on the mainland (Greene and Fraser 1998, Wilson et al. 1998, Ledgard 2010). Brush-tailed possums Trichosurus vulpecula rob nests, being responsible for the failure of six out of 13 nests in Whirinaki during a single breeding season (Greene et al. 2004), and compete for high-energy foods (especially native mistletoe) required for successful breeding (Heather and Robertson 2015, Wilson et al. 1998, Ledgard 2010). Norway rats Rattus norvegicus are also implicated (Moorhouse 1997). Sites with predator control have a nest failure incidence of 16%, compared to 84% in sites without predator control (Moorhouse et al. 2003). Introduced wasps Vespula spp. compete for honeydew, and may be contributing to declines in Nothofagus forests (Beggs and Wilson 1991, Moorhouse 1997).
Conservation Actions Underway
CITES Appendix II. Predator/pest control is carried out in several large areas and around known nest-sites (Greene et al. 2012). Kaka have been successfully released into several pest free sanctuaries (e.g. Maungatautiri, Pukaha/Mt Bruce, Zealandia/Karori, and Orakanui). Successful breeding has been recorded at both Pukaha/Mt Bruce and Zealandia/Karori with both populations increasing steadily in conjunction with effective pest control. Landscape scale pest control is now being conducted in a number of large areas (> 30,000 ha) throughout New Zealand and the response by kaka has been marked (e.g. Greene et al. 2010, Greene et al. 2012). Results strongly suggest that predator control has a positive influence on the incidence of successful fledging (Ledgard 2010) and abundance. Supplementary foods were trialled where wasps are a major problem, but did not increase productivity (Wilson et al. 1998). Radio-tracking is used to identify adult and juvenile movements and survival, habitat requirements and important food sources.
Conservation Actions Proposed
Continue large-scale pest control to benefit this and other forest species (i.e. Battle for our Birds) (T. Greene in litt. 2016).
45 cm. Vocal forest parrot. Crimson underwings, rump, collar. Golden cheeks. North Island subspecies, mainly olive-brown. Dark feather edges. Paler, greyer crown. South Island subspecies, brighter. Crown almost white. Longer bill, more arched in males. Juvenile has yellow base of mandible. Similar spp. Kea N. notabilis is much larger, olive-green all over with scarlet underwing, dark red rump. Voice Noisy, varied, from whistling to grating calls.
Text account compilers
Benstead, P., Harding, M., Khwaja, N., Mahood, S., McClellan, R., Taylor, J., Stringer, C.
Moorhouse, R., Greene, T., Hitchmough, R.
BirdLife International (2020) Species factsheet: Nestor meridionalis. Downloaded from http://www.birdlife.org on 14/07/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 14/07/2020.