|Scientific Name:||Nesospiza wilkinsi|
|Species Authority:||Lowe, 1923|
|Taxonomic Notes:||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.|
|Red List Category & Criteria:||Endangered D ver 3.1|
|Reviewer/s:||Butchart, S. & Taylor, J.|
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.
|Range Description:||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.|
Native:Saint Helena, Ascension and Tristan da Cunha
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||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.|
|Habitat and 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.|
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).
|Citation:||BirdLife International 2012. Nesospiza wilkinsi. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 20 May 2013.|
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