Data Zone
Justification of Red List category
Although this species has a restricted area of occupancy, it is not believed to approach the thresholds for Vulnerable under the range size criterion given that there is no evidence of a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation. The population trend is increasing, and hence does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). Although the population size numbers less than 10,000 mature individuals, without a continuing decline it does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). It is therefore evaluated as Least Concern.
Population justification
The population is suspected to have recently surpassed 5,000 mature individuals as a result of ongoing conservation management, with the 2020 Conservation status of New Zealand birds (Robertson et al. 2021) now placing the population in the bracket 5,000-20,000 mature individuals (the species was placed at 1,000-5,000 in 2016). The estimate of 5,000 mature individuals is followed here.
Trend justification
The population is inferred to be increasing owing to documented translocations and intensive conservation action such that it now numbers over 5,000 mature individuals (Robertson et al. 2021), and additional translocations are ongoing to predator-free islands where the species can quickly become abundant (Masuda and Jamieson 2013).
Philesturnus carunculatus was once widespread through the South and Stewart Islands, New Zealand. Predation by introduced mammals (mainly ship rats) led to their extinction on the South Island and Stewart Island by about 1900, and they became confined to the South Cape Islands (Big South Cape, Solomon and Pukeweka Islands), islands off the south-west coast of Stewart Island (Merton 1975, Heather and Robertson 1997). When ship rats invaded all three islands in the early 1960s, the Wildlife Service (which subsequently became part of the Department of Conservation) successfully moved birds from Big South Cape Island to nearby Big and Kaimohu Islands in 1964, thereby averting the extinction of this species. Up to 2013, subsequent successful translocations have been made to Betsy Island (1969), Womens Island (1972), North Island (1972), Putauhinu Island (1974, 1976, 1984), Kundy Island (1978), Edwards/Motunui Island (1981), Jacky Lee Island (1986), Breaksea Island (1992), Motuara Island (1994), Pohowaitai (1999), Ulva Island (2000), South Passage Island, Chalky Inlet (2001), Anchor Island (2002, 2004), Long Island (2005), Chalky Island, Fiordland (2008), Blumine Island (2009-10), Big South Cape (2011-12, following 2006 rat eradication), Big Moggy Island (2011), Little Moggy Island (2012), and Solomon Island (2012) [Masuda and Jamieson 2013].
It inhabits native forest, nesting in tree holes, rock crevices, tree-fern crowns and dense epiphytes, usually close to the ground. Whilst it also occurs in replanted forest, it is thought that mortality is higher in this habitat (Brunton and Stamp 2007). It forages in leaf litter and deadwood, predominantly on invertebrates, but will also take fruits and nectar (Taylor and Jamieson 2007). It is not a strong flier and bounds between branches or along the ground rather than taking long flights. It usually raises one brood in October-January but will nest up to four times at recently colonised sites where resources are not limiting.
Introduced carnivorous mammals probably caused its extinction on the mainland. The arrival of Black Rat Rattus rattus on the three Stewart Island islets in 1963 caused the rapid extinction of the populations. P. carunculatus cannot coexist with Brown Rat R. norvegicus or Pacific Rat R. exulans (Lovegrove 1996). The accidental introduction of such species to further islands is an ever-present threat, although mitigated on a global level by the large number of islands the species has now been re-introduced/introduced to. Fire is also a threat, particularly with the combination of resident people, peat soil and windy conditions on some islands (Roberts 1994). Avian malaria and avian pox have been identified in individuals on Long Island, although at present they appear restricted to this population; both could pose a major threat if the diseases spread (Hale 2008).
Conservation Actions Underway
Intensive management of surviving populations has helped this species to recover and its range has increased in recent years through reintroductions to predator free islands, which are ongoing. Additional captive populations exist.
25 cm. Glossy black bird with bright chestnut saddle. Chestnut rump, tail coverts. Orange-red wattles at base of black bill. North Island subspecies; thin buff line at upper edge of saddle. Juvenile; smaller wattles. Lacks buff line. South Island subspecies; juvenile; brown with red-brown tail coverts. Voice Loud cheet, te-te-te-te.
Text account compilers
Vine, J., Martin, R., Berryman, A.
Contributors
Benstead, P., Harding, M., Khwaja, N., Stringer, C., Stringer, C., Taylor, J. & Westrip, J.R.S.
Recommended citation
BirdLife International (2024) Species factsheet: South Island Saddleback Philesturnus carunculatus. Downloaded from
https://datazone.birdlife.org/species/factsheet/south-island-saddleback-philesturnus-carunculatus on 19/12/2024.
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 19/12/2024.