CR
Mauritius Olive White-eye Zosterops chloronothos



Taxonomy

Taxonomic note
Zosterops chloronothos (del Hoyo and Collar 2016) was previously listed as Zosterops chloronothus.

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
Dowsett, R. J.; Forbes-Watson, A. D. 1993. Checklist of birds of the Afrotropical and Malagasy regions. Tauraco Press, Li
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
A3bce+4abce; C1+2a(ii) A3bce+4abce; C1+2a(i,ii); D A2abce+3bce+4abce; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C

Red List history
Year Category Criteria
2016 Critically Endangered A3bce+4abce; C1+2a(ii)
2012 Critically Endangered C2a(ii)
2009 Critically Endangered C2a(ii)
2008 Critically Endangered
2004 Critically Endangered
2000 Endangered
1996 Critically Endangered
1994 Critically Endangered
1988 Threatened
Species attributes

Migratory status not a migrant Forest dependency High
Land mass type Average mass 8.100000381 g
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 100 medium
Extent of Occurrence breeding/resident (km2) 32 medium
Number of locations 8 -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 191-327 good estimated 2012
Population trend Decreasing good estimated -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 100 - - -
Decline (10 years/3 generation past and future) 100 - - -
Number of subpopulations 2 - - -
Largest subpopulations 1-89 - - -
Generation length (yrs) 3.5 - - -

Population justification: The population estimate of 191-327 mature individuals is derived from 160-296 mature individuals on the mainland (from Nichols et al. [2004] and Ormsby et al. [2012]) and a population of 46 individuals (roughly equivalent to 31 mature individuals) on Iles aux Aigrettes (Ferrière et al. 2015).

Trend justification: Surveys have revealed that the population size declined from an estimated 346 pairs in 1975 to c.200 pairs in 1993 and 93-148 pairs in 2001 (Nichols et al. 2004), and just 7-17% of nesting attempts successfully fledged one chick between 1998 and 2001, hence current rapid declines are likely to continue into the future. Maggs (2016) conducted a population viability analysis of this species and concluded that the population would go extinct within 50 years; this may even be the case within 3 generations as Maggs et al. (2015) extrapolated from current declines to project 14% declines per annum.


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Mauritius N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Mauritius Black River Gorges National Park and surrounding areas
Mauritius Macchabé - Brise Fer forest
Mauritius Relict Forests of the Central Plateau

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Plantations major non-breeding
Forest Subtropical/Tropical Moist Montane major resident
Altitude 200 - 600 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops Timing Scope Severity Impact
Past, Unlikely to Return Majority (50-90%) Negligible declines Past Impact
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting Timing Scope Severity Impact
Past, Unlikely to Return Majority (50-90%) Negligible declines Past Impact
Stresses
Ecosystem degradation, Ecosystem conversion
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Future Whole (>90%) Unknown Unknown
Stresses
Indirect ecosystem effects, Ecosystem degradation
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases Timing Scope Severity Impact
Unknown Unknown Unknown Unknown
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Problematic native species/diseases Timing Scope Severity Impact
Unknown Unknown Unknown Unknown
Stresses
Reduced reproductive success

Recommended citation
BirdLife International (2017) Species factsheet: Zosterops chloronothos. Downloaded from http://www.birdlife.org on 17/10/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 17/10/2017.