• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Justification of Red List category

This species is classified as Vulnerable because it has a very small range (a single remnant population on 28 km² Hauturu/Little Barrier island) such that it is susceptible to stochastic events and the impacts of human activities. The plausible threat of introduced predators could drive the species to Critically Endangered or Extinct in a very short time period. Intensive conservation efforts aim to improve its status, but these have resulted in only partial success with translocated populations requiring intensive and ongoing management.

Population justification

The population on Little Barrier was estimated to be 3,100 mature individuals in 2013, assumed to equate to a total population of over 4,500 individuals, based on density estimates from distance sampling (Toy et al. 2018). This estimate is thought to remain applicable given that the population trend is stable and has been throughout the last three generations (Robertson et al. 2013, 2017, 2021). There are estimated to be 626 mature individuals across the six translocated populations, based on re-sighting and breeding data: Tiritiri Matangi Island (193), Kapiti Island (107), Zealandia (120), Maungatautari (104), Rotokare (56) and Bushy Park (46) (Parlato et al. 2021). These populations are not counted in the total since their survival relies on ongoing intensive management, meaning that they do not qualify as wild populations sensu IUCN and are not included in the assessment.

Trend justification
Although densities appear to fluctuate on Little Barrier (Toy et al. 2018), overall the population trend is estimated to have remained stable throughout the last three generations (Robertson et al. 2013, 2017, 2021).

Notiomystis cincta was once widespread over the North Island and adjacent offshore islands of New Zealand. Little Barrier Island (28 km²) is now the last natural population. Translocated populations exist on Kapiti (20 km²), Tiritiri Matangi (2 km²), Zealandia Wildlife Sanctuary (2.25 km²) and at Maungatautari (34 km²). Birds have also been translocated to Bushy Park and Rotokare (Casto 2020). None of the translocated populations are self-sustaining and most are only increasing as a result of intensive and ongoing management including supplementary feeding and predator control at all sites, and the provision of nesting boxes and parasite control at most sites (Armstrong and Ewen 2001, Armstrong et al. 2002, Chauvenet et al. 2012).

It is found in most forest types, but requires mature forest for breeding as it nests in tree-cavities. It feeds on nectar, fruit and arthropods, depending on availability and requirements (Angehr 1984, Castro et al. 1994b). It has a highly variable breeding system, and is the only bird species known to mate facing each other (Castro et al. 1996). Forced copulation by males occurs during the breeding season (Low 2005). Rates of extra-pair paternity are very high (about 60% of offspring; Brekke et al. 2012). It lays between three and five eggs and can lay up to three clutches per breeding season, but can only rear a maximum of two.

Its extinction on the mainland may have been due to the introduction of mammalian predators such as black rats Rattus rattus and/or avian disease (Angehr 1984). It also declined owing to forest loss in parts of its range (Department of Conservation 2005). Factors limiting the translocated populations have not yet been confirmed (D. P. Armstrong in litt. 1999), but declines in the translocated population on the island of Mokoia were attributed to aspergillosis and the discontinuation of supplementary feeding (Castro et al. 2003), and declines on Tiritiri Matangi have been attributed to an outbreak of salmonella (Ewen et al. 2007). All translocated populations are reliant on supplementary feeding. The recovery of translocated small island populations may be hindered by inbreeding depression (Brekke et al. 2010). It appears to require large expanses of mature forest to survive which represents a major hurdle to conservation efforts (I. Castro in litt. 1999). Most recent translocations have been to restored mainland areas that have more mature and diverse forest habitats, however this raises concerns with dispersal outside of protected areas. Dispersal likely caused translocation failure at one site (Ewen et al. 2013).

Conservation Actions Underway
Translocations were initiated in 1980 and have had mixed success. Stitchbirds have been translocated with success to Kapiti Island (1983-84, 1990-92, 2002), Tiritiri Matangi Island (1995-96, 2001, 2010), Karori Sanctuary (Zealandia; 2005-06, 2008, 2010), Maungatautari (2009-11), Bushy Park (2013), and Rotokare (2017-18) (Casto 2020). Translocated birds are given supplementary food, and nest boxes are usually provided. Research to identify factors limiting the new populations indicates that translocation methods and availability of food were not key issues on Mokoia yet the population had poor viability and the last remaining birds were removed in 2002 (Armstrong et al. 1999, Armstrong and Perrott 2000), but food shortages and competition for food with endemic honeyeaters may be a problem on Kapiti (Castro et al. 1994a; Chauvenet et al. 2012) and Tiritiri Matangi (Armstrong and Ewen 2001). Initial signs of population establishment are promising for Karori, Maungatautari (Ewen et al. 2011) and Bushy Park Sanctuary. Further sites are being assessed as potential locations for translocation. A small captive population is held, but numbers have gradually declined (Rasch et al. 1996) and the project will be discontinued as it is not cost efficient compared to sourcing wild bred birds for translocation. The population on Little Barrier Island is monitored and efforts are ongoing to generate an accurate population assessment. In 2020, a seventh reintroduced population was established at Shakespear Open Sanctuary.

Conservation Actions Proposed
Protect, monitor and, where necessary, enhance populations on existing transfer sites. Research the species' requirements to aid establishment of populations and with a desire to reduce each populations' dependency on management support. Raise public awareness and appreciation of the species (Armstrong 1996). Continue monitoring the population using distance sampling on Little Barrier and investigate factors influencing density (Toy et al. 2018).

18 cm. Small, sexually dimorphic passerine. Male, distinctive velvet-black head, back, upper breast. White erectile ear-tufts. Black underlined on breast with golden-yellow. Black wings with golden-yellow shoulder patches, white wing-bars. Remainder of underparts pale brown. Female, grey-brown with white wing-bar. Some females have small, non-distinctive white ear-tufts. Voice Male, loud explosive whistle see-si-ip, low warbling song of up to three minutes. Alarm calls stitch, whee whee whee.

Text account compilers
Vine, J.

Contributors
Armstrong, D.P., Boyd, S., Brekke, P., Castro, I., Ewen, J., Richardson, K., Symes, A., Butchart, S., Benstead, P., McClellan, R., Wheatley, H., Bird, J., Taylor, J. & Khwaja, N.

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Recommended citation
BirdLife International (2024) Species factsheet: Stitchbird Notiomystis cincta. Downloaded from https://datazone.birdlife.org/species/factsheet/stitchbird-notiomystis-cincta on 23/11/2024.
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 23/11/2024.