Data Zone
Justification of Red List category
This species was once comprised of just five individuals, however conservation action now sees it occur at 11 locations: eight offshore islands and three fenced mainland sanctuaries. The population size is currently 1,500 mature individuals, and continues to increase. However, over 70% of the population occurs on one island, where, if mammalian predators were to accidentally be introduced, the population could become Vulnerable or Endangered in a very short period of time. It is therefore listed as Near Threatened.
Population justification
The population was estimated to number 1,900 individuals in total in 2018 (Germano et al. 2018), roughly equivalent to 1,500 mature individuals. Kapiti is the stronghold for the species, where approximately 70% of the population occurs (Robertson 2013).
Trend justification
Overall the species is estimated to be increasing and this trend is predicted to continue (Robertson et al. 2021). The total number of individuals increased from 1,500 in 2008 to 1,900 in 2018, and is projected to reach 2,750 by 2030 with existing levels of management (Germano et al. 2018). On Kapiti the species is considered to be at carrying capacity and annual survivorship has been estimated at 97.5% (Robertson and Colbourne 2004). This population is being used to increase populations on other islands or to establish new populations (Holzapfel et al. 2008).
Apteryx owenii (or allied species) occurred in forested areas throughout New Zealand prior to European settlement, but A. owenii is now restricted to eight offshore islands to which it has been introduced, and three mainland sites where it has been reintroduced (Germano et al. 2018). The stronghold is Kapiti Island (20 km2), where five birds are believed to have been introduced in 1912 (Ramstad et al. 2013). In the 1980s, birds were released on Red Mercury (2 km2), Hen (5 km2) and Long Islands (2 km2), and to Tiritiri Matangi Island (2 km2) in 1993 and 1995 (Colbourne and Robertson 1997). Birds have also been released on Motuihe Island (2 km2) in 2009 (Anon. 2009), Chalky Island (5 km2) in 2008-2010 (Edmonds 2010), Anchor Island (15 km2) in 2015-16 (ongoing) and at Cape Sanctuary (1 km2) near Napier in the North Island (ongoing). Birds were also reintroduced to Shakespear Open Sanctuary in 2017 (Germano et al. 2018).
It is present in all available habitats on Kapiti, including mature broadleaf forest, regenerating forest and grassland (Marchant and Higgins 1990). It eats invertebrates, but also fallen fruits and leaves (Heather and Robertson 2015). It lays one, sometimes two eggs, usually in a burrow. Chicks hatch fully-feathered, and first leave the nest unaccompanied after about a week. It normally begins to breed at around three years of age (H. A. Robertson in litt. 1999). Mean life expectancy is estimated at 45 (27-83) years (Robertson and Colbourne 2004).
Introduced predators except Weka Gallirallus australis are absent from all the islands where A. owenii occur. There are conflicting reports as to the extent and effect of predation (Jolly 1989, Marchant and Higgins 1990), although the A. owenii population appears to have grown since 1912 in the presence of Weka (H. A. Robertson in litt. 2016). The island populations remain susceptible to accidental or deliberate introduction of mammalian predators. The genetic diversity of the species is very low, having passed through a bottleneck of just five individuals (including at least two females), and there has been further loss of genetic diversity with each transfer from Kapiti Island (Ramstad et al. 2021).
Conservation Actions Underway
Translocations to predator-free offshore islands have done much to secure the survival of A. owenii, and the species has been reintroduced to three mainland sites (Germano et al. 2018). More islands have been examined for further introductions, but given the health of the present island populations, and their geographical spread, there is limited need for additional island populations; however, other secure mainland sites are being investigated to allow people access to the species. Research has shown that neither of the D'Urville Island birds placed on Long Island (Marlborough Sounds) with two Kapiti Island birds has left any descendants and so the entire population is derived from a single pair and is highly inbred (Taylor 2014). Two hybrid offspring from A. owenii x A. rowi pairings have been discovered in South Okarito forest since 1993, suggesting that A. owenii must have been present in the area until the mid-1990s and so nearby reports of kiwi are being checked, and elsewhere in the South Island, young (i.e. small) A. haastii are critically examined in case a few A. owenii persist on the South Island mainland. All populations are monitored using call-counts, and territory-mapping, and specially-trained dogs are used to locate banded birds (H. A. Robertson in litt. 2016). To reduce the risk of inbreeding depression and increase genetic diversity, 10 birds each from Tiritiri and Red Mercury were replaced with individuals from Kapiti, with the removed individuals used to establish populations at Cape Sanctuary and Shakespear Open Sanctuary (Robertson et al. 2019).
30 cm. Smallest kiwi, flightless, no visible wings. Brownish-grey with fine, white horizontal mottling. Pale legs and long ivory bill. Voice High-pitched ascending whistle (male), lower and more tremulous, a rolling churr (female).
Text account compilers
Vine, J., Benstead, P., McClellan, R., Martin, R., Stringer, C., Mahood, S., Taylor, J.
Contributors
Robertson, H.A.
Recommended citation
BirdLife International (2024) Species factsheet: Little Spotted Kiwi Apteryx owenii. Downloaded from
https://datazone.birdlife.org/species/factsheet/little-spotted-kiwi-apteryx-owenii on 24/11/2024.
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 24/11/2024.