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Cleptornis marchei

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA AVES PASSERIFORMES ZOSTEROPIDAE

Scientific Name: Cleptornis marchei
Species Authority: (Oustalet, 1889)
Common Name(s):
English Golden White-eye

Assessment Information [top]

Red List Category & Criteria: Critically Endangered A3e+4e ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Symes, A. & Butchart, S.
Contributor(s): Amidon, F., Hawley, N., Lepson, J., Saunders, A., Tieber, A. & Wiles, G.
Facilitator/Compiler(s): Benstead, P., Bird, J., Derhé, M., Mahood, S., O'Brien, A., Shutes, S., Stattersfield, A., Symes, A.
Justification:
The majority of the population of this species occurs on the island of Saipan, where the brown tree snake Boiga irregularis may be in the process of becoming established. This is likely to lead to an extremely rapid population reduction in the near future, unless the snake can be controlled. It therefore qualifies as Critically Endangered.

Geographic Range [top]

Range Description: Cleptornis marchei is endemic to the Northern Mariana Islands (to USA), occurring on Saipan where, in 2007, the population was estimated at 71,997 birds, and on the uninhabited Aguijan (4 km2), where the population was estimated at 1,169 birds (Camp et al. 2009, Amidon et al. in prep.). Populations on Saipan have declined since 1982 while surveys conducted in 2008 indicate that densities on Aguijan were significantly greater in 2008 than in 1982 (Camp et al. 2009, Amidon et al. in prep). On Saipan, estimated densities from surveys during 1991-1992 were among the highest ever reported for birds (up to 2,095 birds/km2), suggesting that numbers were likely to be at carrying capacity for the island (Craig 1996). Island-wide surveys on Saipan in 1997 indicated that the population may have been declining but no population estimates were calculated (USFWS 1999). Population densities were recalculated for 1982 and calculated for surveys conducted in 1997 and 2007 (Camp et al. 2009).  Population densities (birds per km2 ±SE) on Saipan declined from 1,287.2 ± 191.0 in 1982, 995.5±160.0 in 1997 and 711.8±112.1 in 2007 (Camp et al. 2009).

Countries:
Native:
Northern Mariana Islands
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The species occurs on Saipan (71,997 individuals) and Aguijan (1,169 individuals) (Camp et al. 2009, Amidon et al. in prep.), equating to a global population of c.73,000 individuals.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: On Saipan, it occurs in all wooded habitats, including the native limestone forest (which is restricted to steep slopes and cliffs and covers c. 5% of the island), and introduced tangan tangan Leucaena leucocephala thickets on flat lowlands and plateaus (c. 28% of land cover), and also urban areas (Pratt et al. 1987, Craig 1990, A. Tieber in litt. 2008, 2010). However, it is decidedly more common in limestone forest than in disturbed areas (Craig 1996), and higher nesting densities are recorded in limestone forest than tangan tangan thickets (Sachtleben 2005). It forages predominantly in the foliage of trees, particularly Cynometra ramifolia, feeding on invertebrates, flying insects, nectar, fruit and flowers and also taking insects from tree bark (Pratt et al. 1987, Craig 1990) and is typically seen in small groups of 2-4 individuals, thought to be family groups (A. Tieber in litt. 2008, 2010).

Systems: Terrestrial

Threats [top]

Major Threat(s): The species's ability to utilise different habitats may help to explain its persistence despite periodic typhoon damage and extensive, human-caused habitat change (Craig 1990). The potential establishment of brown tree snake Boiga irregularis on Saipan poses a major threat to the population (Rodda and Savidge 2007) and would likely lead to extremely rapid declines, as has been the case amongst the endemic avifauna of Guam (to USA) (A. Saunders in litt. 2003, Wiles et al. 2003, Williams 2004), but there are no data as yet on predation of the white-eye (A. Tieber in litt. 2008, 2010). Aguijan is difficult to get to and it is unlikely that snakes will be accidentally introduced there (J. Lepson in litt. 1999) - as of 2008 there had been no reports of snakes on the island (A. Tieber in litt. 2008, 2010). Having a distribution on relatively low-lying islands, this species is potentially susceptible to climate change through sea-level rise and shifts in suitable climatic conditions (BirdLife International unpublished data).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Although not directed solely at the conservation of this species, extensive efforts are underway to determine the status of brown tree snake Boiga irregularis on Saipan and should an established population be identified, to control it immediately (N. Hawley in litt. 2007). Efforts are also underway to develop captive breeding techniques for the species. Golden white-eyes were translocated to the island of Sarigan in 2011 and a second translocation is proposed for 2012 (Berger et al. 2005). In 2007 and 2008 a total of 46 birds were taken into captivity as part of the Marianas Avifauna Conservation Plan with the intention of beginning captive breeding in the near future (A. Tieber in litt. 2008, 2010). As of 2010 there are currently 38 chicks dispersed throughout six institutions in the U.S., all developing captive breeding protocols. Two chicks were produced in 2009, though only one survived (A. Tieber in litt. 2008, 2010).

Conservation Actions Proposed
Monitor population trends through detailed censuses (G. Wiles in litt. 1999). Continue to control Boiga irregularis population by trapping at ports and monitor its spread. Develop and implement techniques to control small incipient populations of B. irregularis (F. Amidon in litt. 2007). Continue to develop techniques for establishing a captive population and establish new wild populations, as appropriate (F. Amidon in litt. 2007). Continue to monitor the translocated population on Sarigan.


Citation: BirdLife International 2012. Cleptornis marchei. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 01 October 2014.
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