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

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.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
A3bce+4abce; C2a(ii)	A3bce+4abce; C2a(i,ii); D	A2abce+3bce+4abce; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(i,ii); D1+2

Red List history

Year	Category	Criteria
2016	Critically Endangered	A3bce+4abce; C2a(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

Migratory status	not a migrant	Forest dependency	high
Land-mass type		Average mass	8 g

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	100 km2	medium
Area of Occupancy (breeding/resident)	32 km2	medium
Number of locations	8	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	191-327 mature individuals	good	estimated	2012
Population trend	decreasing	good	estimated	2012-2023
Rate of change over the past 10 years/3 generations (longer of the two periods)	30-49%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	100%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	100%	-	-	-
Generation length	3.5 years	-	-	-
Number of subpopulations	2	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

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	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Mauritius	extant	native	yes

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

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

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Small-holder farming	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 - Unintentional effects: (subsistence/small scale) [harvest]	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 - Ligustrum robustum	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 - Psidium cattleianum	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 - Pycnonotus jocosus	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 - Rattus norvegicus	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 - Rattus rattus	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 - Hypsipetes olivaceus	Timing		Scope		Severity		Impact
		Unknown		Unknown		Unknown		Unknown
		Stresses Reduced reproductive success

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Recommended citation
BirdLife International (2024) Species factsheet: Mauritius Olive White-eye Zosterops chloronothos. Downloaded from https://datazone.birdlife.org/species/factsheet/mauritius-olive-white-eye-zosterops-chloronothos on 22/11/2024.
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 22/11/2024.