Data Zone
Justification of Red List category
This species is increasing in number following intensive conservation management. However, the total population remains small and it is therefore classified as Vulnerable.
Population justification
The 2019 population is estimated to number 500-600 adults (G. Coleman in litt. 2019) and given that some (presumably very old) birds do not breed, the number of mature individuals is estimated to lie in the range 350-400 birds. There is one subpopulation on the west coast of the South Island.
Trend justification
The population has risen rapidly from c.160 birds in 1995 to 500-600 adults in 2019 (G. Coleman in litt. 2019) following intensive captive rearing of eggs and chicks to avoid predation by invasive stoats (H. Robertson in litt. 2016).
Apteryx rowi is locally common in native lowland forests in a small area of coastal forest inland from Okarito, on the west coast of South Island, New Zealand (Robertson 2013). It has recently been introduced to Mana (in 2012), Motuara and Blumine Islands (in 2010), in the Cook Strait region, and breeding has been recorded at both Mana and Blumine (H. Robertson in litt. 2016). However, there is a plan to eventually move any birds bred on these islands back to the South Island (Friends of Mana Island, n.d.). Subadult birds have been released in adjacent North Okarito in 2018 (G. Coleman in litt. 2019), which was part of the species's range until very recently, and they have started breeding there. Sub adult birds have been released in the Omoeroa ranges between Fox and Franz Josef to establish a new population. Before human settlement of New Zealand, the species was widespread throughout the northern South Island and into the southern North Island, as far north as Lake Poukawa (Hawkes Bay) (Robertson 2013).
The native population is now restricted to coastal podocarp-hardwood forest. Eggs are laid from July to January, and the clutch size is one, but sometimes clutches can be overlapped. The nest is in a burrow, hollow base of a tree, or in a hollow log. The species is flightless and nocturnal, resting by day in a burrow, hollow tree or log or under thick vegetation. It feeds by walking slowly along tapping the ground, probing the bill into leaf litter or rotten logs when food is detected. Food is mostly small invertebrates, especially earthworms and larvae of beetles, cicadas and moths (Robertson 2013).
The species underwent massive historic declines and disappeared from most of its former range as a result of a combination of habitat loss and predation by introduced mammals. Declines up until the 1990s were attributed to recruitment failure caused by predation of chicks and juveniles by stoats Mustela erminea, and some adults being killed by dogs and motor vehicles.
Conservation and research actions underway
'Operation Nest Egg', which involved the removal of eggs or young chicks from the wild and rearing in captivity and on Motuara Island, until large enough to cope with the presence of stoats, allowed the population to increase (Colbourne et al. 2005). A landscape-scale stoat trapping programme in South Okarito Forest from 2001-2005 largely failed to protect chicks from stoat predation. Operation Nest Egg was reinstated, leading to the recent rapid population growth. New populations have been established on Mana and Blumine Islands, and breeding has been recorded at both of these sites (H. Robertson in litt. 2016). There is a plan to eventually move any birds bred on these islands back to the South Island (Friends of Mana Island, n.d.). In 2019, the first translocation of sub-adults from Mana Island back to the mainland occurred (G. Coleman in litt. 2020). Subadult birds have been released in adjacent North Okarito, which was part of the species's range until very recently, and they have started breeding there. In 2018, the Okarito site was considered at capacity, so a new site was established in the Omoeroa ranges between Fox and Franz Josef. Ongoing Operation Nest Egg recruits will continue to be released here.
Conservation and research actions proposed
Undertake population modelling to inform ongoing management. Continue to monitor the population size.
Implement landscape scale control of stoats (Germano et al. 2018). Continue Operation Nest Egg to supplement new populations and ensure genetic management, with the aim to move towards less-intensive management, survival and reproduction in the wild in the long term (Germano et al. 2018). Encourage dog owners to undertake kiwi avoidance training. Promote legislative and policy changes to protect populations and encourage high-quality advocacy at all levels (Robertson 1998, Holzapfel et al. 2008). Educate and inform the public and encourage community involvement in Kiwi conservation (Robertson 1998, Holzapfel et al. 2008).
40 cm. Medium-sized kiwi, flightless, no visible wings. Dark greyish-brown feathers streaked lengthways with reddish-brown. Long ivory bill. Similar spp. Okarito birds distinguished from Tokoeka A. australis by slightly greyer plumage, occasional white facial whiskers. Voice Shrill, clear ascending then descending whistle (male), lower-pitched, hoarse cry (female). Note duration and inter-note interval increase during a calling bout, and there is evidence that the species may duet (Corfield et al. 2008). Hints Loud calls at night, especially first two hours of darkness.
Text account compilers
Simkins, A., Wheatley, H.
Contributors
Robertson, H.A., Weeber, B., Germano, J., Coleman, G., Symes, A., Taylor, J., Martin, R., Benstead, P., Mahood, S. & McClellan, R.
Recommended citation
BirdLife International (2024) Species factsheet: Okarito Kiwi Apteryx rowi. Downloaded from
https://datazone.birdlife.org/species/factsheet/okarito-kiwi-apteryx-rowi on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/12/2024.