• 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
-	C2a(i); D	C2a(i); D1

Red List history

Year	Category	Criteria
2024	Endangered	C2a(i); D
2016	Endangered	C2a(i)
2012	Endangered	B1ab(ii,iii,v);C2a(i)
2008	Endangered	B1a+b(ii,iii,v)
2004	Endangered
2000	Endangered
1996	Vulnerable
1994	Vulnerable
1988	Lower Risk/Least Concern

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	1,380 km2	medium
Area of Occupancy (breeding/resident)	640 km2
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	125-250 mature individuals	poor	estimated	2022
Population trend	decreasing	poor	inferred	-
Generation length	4.89 years	-	-	-
Number of subpopulations	2	-	-	-
Percentage of mature individuals in largest subpopulation	75%	-	-	-

Population justification: This species is patchily distributed and difficult to find, seemingly absent from large tracts of suitable upland habitat (O'Brien and Masibalavu 2017, M. O'Brien in litt. 2022). It was found to be common but patchily distributed in Savai'i highland forests in 2005 (Pratt and Mittermeier 2016). The Rapid Biodiversity Assessment of Upland Savai'i, Samoa, conducted in 2012, detected small numbers at two sites on the island (Butler 2012). The ICCRIF study of 2014 found it at only one of five sites it surveyed (R. Stirnemann in litt. 2016), and during surveys of multiple sites in 2016 the species was recorded on point counts only at Aopo (O'Brien and Masibalavu 2017, M. O'Brien in litt. 2022). Based on point count data from 2016, there were crudely estimated to be 1 pair for every 16 to 22km² overall, equating to c. 50 mature individuals on Savai'i (M. O'Brien in litt. 2022). However, although its call is far-reaching, the species' detectability is otherwise very low and this is likely to be an underestimate (though the subpopulation is not thought to exceed 250 mature individuals) (M. O'Brien in litt. 2022). As such, the population on Savai'i is tentatively placed in the band 100-200 mature individuals, with the global population placed at 125-250 mature individuals under the assumption that c.75% of the population occurs on Savai'i.

Trend justification: Although the species was considered common in preferred upland habitat on `Upolu and Savai'i in 1984 (Bellingham and Davis 1988), it has reportedly become rarer and appears to be absent from sites it was recorded at previously (e.g. Uafato) (M. O'Brien in litt. 2022). The species is mostly restricted to montane forest and declines are believed to be associated with habitat loss and degradation, as well as high rates of nest failure and predation (USFWS 2020). A decline in distribution in the 1990s it thought to have been driven by a series of cyclones (Lovegrove et al. 1992, Park et al. 1992), and surveys in 2005-2006 indicated that numbers were continuing to decline (MNRE 2006, USFWS 2020). Nest predation by Black rat Rattus rattus has been shown to impact reproductive success (Stirnemann et al. 2015a) and the species appears to have increased following rat control in Malololelei (M. O'Brien in litt. 2022). This threat acts parallel to that of habitat loss and fragmentation, with nests near plantations or on forest edge likely experiencing higher predation rates than those in interior forest (Stirnemann et al. 2015a). These threats are thought to be especially impactful for this species due to its slow life history traits. As the threats are ongoing, a continuing decline is inferred.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
American Samoa	extinct	native	yes
Samoa	extant	native	yes

Country/Territory	IBA Name
Samoa	Apia Catchments
Samoa	Central Savaii Rainforest
Samoa	Eastern Upolu Craters
Samoa	O Le Pupu-Pu'e National Park
Samoa	Uafato-Tiavea Forest

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Plantations	suitable	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Forest	Subtropical/Tropical Moist Montane	major	resident
Shrubland	Subtropical/Tropical High Altitude	marginal	resident
Altitude	760 - 1800 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Agro-industry farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Annual & perennial non-timber crops - Shifting agriculture	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Annual & perennial non-timber crops - Small-holder farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Hunting & trapping terrestrial animals - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Unknown		Minority (<50%)		Unknown		Unknown
		Stresses Species mortality
Biological resource use	Logging & wood harvesting - Unintentional effects: (large scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Climate change & severe weather	Storms & flooding	Timing		Scope		Severity		Impact
		Past, Likely to Return		Majority (50-90%)		Rapid Declines		Past Impact
		Stresses Ecosystem degradation
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Bos taurus	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Indirect ecosystem effects, Ecosystem degradation
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Felis catus	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Named species	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Reduced reproductive success, Species mortality
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, Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Sus scrofa	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Indirect ecosystem effects, Ecosystem degradation
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Unspecified species	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation
Residential & commercial development	Housing & urban areas	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion

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Recommended citation
BirdLife International (2024) Species factsheet: Mao Gymnomyza samoensis. Downloaded from https://datazone.birdlife.org/species/factsheet/mao-gymnomyza-samoensis on 23/11/2024.
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 23/11/2024.