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Wilkins's Bunting Nesospiza wilkinsi
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Justification
This recently-split species is listed as Endangered as it has an extremely small population which is threatened by habitat loss, with potential causes including invasive species, storms and wood-cutting.

Taxonomic source(s)
Ryan, P. G. 2008. Taxonomic and conservation implications of ecological speciation in Nesospiza buntings at Tristan da Cunha. Bird Conservation International 18(1): 20-29.

Taxonomic note
Nesospiza acunhae (Sibley and Monroe 1990, 1993) has been split into N. acunhae (Inaccessible Island) and N. questi (Nightingale Island), while subspecies N. wilkinsi dunnei (Inaccessible Island) has been transferred to N. acunhae following Ryan et al. (2007) and Ryan (2008) who provide compelling phylogenetic evidence for this arrangement and point out the morphological and vocal differences supporting the treatment of paraphyletic forms questi and acunhae as species.

Identification
18 cm. Large-billed, island bunting. Uniform olive-green above with yellowish-green underparts which show streaking on belly and flanks. Yellow face and throat with prominent, short, yellow eyebrow-stripe. Similar spp. Superficially resembles Tristan Bunting N. acunhae but differs chiefly in having unusually disproportionate, massive bill, also paler yellow underparts with streaking on flanks and belly.

Distribution and population
Nesospiza wilkinsi is restricted to Nightingale Island, Tristan da Cunha (St Helena to UK), in the South Atlantic Ocean (Ryan 2008). It rare on the island and may number between 50 and 100 pairs (Ryan 1992, P. G. Ryan in litt. 1999, 2010), with other estimates suggesting fewer than 120 birds (Ryan 2008). The total population has probably always been small (Fraser and Briggs 1992), but may have increased slightly since the 1950s.

Population justification
The population is currently thought to be around 100 pairs (P. G. Ryan in litt. 2009), hence a population band of 50-249 mature individuals seems appropriate.

Trend justification
The species's population is suspected to be stable owing to the absence of any serious and immediate threats.

Ecology
It is largely restricted to areas which support some Phylica arborea trees, but also regularly occurs in tussock-grassland. The breeding season is from December to February, with nests located in clumps of vegetation near ground-level.

Threats

Visits to Nightingale can now be made by islanders via at least two RIBs as well as the fishery patrol vessel and the crayfish vessel operating in Tristan waters (P. G. Ryan in litt. 2012). This species is thus permanently at risk from the accidental introduction of mammalian predators which could prey on eggs, chicks and nesting birds. Another threat is the invasion of the introduced New Zealand flax Phormium tenax into areas of Phylica, but initial clearing in 2004 and ongoing follow-up operations have largely eliminated this threat (P. G. Ryan in litt. 2012). It may be benefiting from the cessation of wood cutting by Tristan islanders visiting Nightingale, resulting in some Phylica regeneration, but there are reports that an alien scale insect (common on Tristan and locally common on Inaccessible) is also on Nightingale, which may have significant impacts on fruit production (P. G. Ryan in litt. 2012). On Inaccessible, heavily infested trees have much lower fruit loads than healthy trees. Another potential threat is a black fungus-like growth which has previously from Tristan to Inaccessible, though there is currently no evidence of its presence on Nightingale. It is also potentially threatened by catastrophic weather events and the effects of climate change: strong winds blow down large swathes of Phylica (as happened in 2001), potentially affecting the habitat quite significantly (P. G. Ryan in litt. 2012).



Conservation Actions Underway
No specific conservation actions are currently known for the species. Conservation Actions Proposed
Conduct surveys to obtain an up-to-date population estimate. Carry out regular surveys to monitor population trends. Minimise the risk of introduction of exotic animal or plant taxa, including soil pathogens that could affect important plant species, by strict controls on visits, and promoting awareness of the dangers of inter-island transfers (P. G. Ryan in litt. 1999, 2010). Eradicate New Zealand flax from Nightingale (P. G. Ryan in litt. 1999, 2010).

References
Fraser, M. W.; Briggs, D. J. 1992. New information on the Nesospiza buntings at Inaccessible Island, Tristan da Cunha, and notes on their conservation. Bulletin of the British Ornithologists' Club 112: 191-205.

Ryan, P. G. 1992. The ecology and evolution of Nesospiza buntings. Dissertation. Ph.D., University of Cape Town.

Ryan, P. G. 2008. Taxonomic and conservation implications of ecological speciation in Nesospiza buntings at Tristan da Cunha. Bird Conservation International 18(1): 20-29.

Further web sources of information
Alliance for Zero Extinction (AZE) species/site profile. This species has been identified as an AZE trigger due to its IUCN Red List status and limited range.

Click here for more information about the Alliance for Zero Extinction (AZE)

Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Calvert, R., Symes, A.

Contributors
Ryan, P.G.

IUCN Red List evaluators
Butchart, S., Taylor, J.

Recommended citation
BirdLife International (2014) Species factsheet: Nesospiza wilkinsi. Downloaded from http://www.birdlife.org on 23/09/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/09/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Grosbeak bunting (Nesospiza wilkinsi) 0

Key facts
Current IUCN Red List category Endangered
Family Emberizidae (Buntings, American sparrows and allies)
Species name author Lowe, 1923
Population size 50-249 mature individuals
Population trend Stable
Distribution size (breeding/resident) 2 km2
Country endemic? Yes
Links to further information
- Additional Information on this species