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

Taxonomic note

Acrocephalus caffer, A. musae and A. longirostris (del Hoyo and Collar 2016) were previously lumped as A. caffer following Sibley and Monroe (1990, 1993).

Taxonomic source(s)
Cibois, A.; Thibault, J.-C.; Pasquet, E. 2008. Systematics of the extinct reed warblers Acrocephalus of the Society Islands of eastern Polynesia. Ibis 150(2): 365-376.
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
D	D	D1

Red List history

Year	Category	Criteria
2024	Extinct
2016	Extinct
2012	Not Recognised
2008	Not Recognised
2004	Not Recognised
2000	Not Recognised
1994	Not Recognised
1988	Not Recognised

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

	Estimate	Data quality
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	0 mature individuals	good	estimated	-
Population trend		poor	-	1998-2008
Generation length	2.59 years	-	-	-

Population justification: None remain.

Trend justification: Acrocephalus musae went extinct on the islands of Raiatea and Huahine respectively, in the Society Islands, French Polynesia, in the late 1800s or early 1900s (Hume 2017).

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
French Polynesia	extinct	native	yes

Country/Territory	IBA Name

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Plantations	possible	unknown
Forest	Subtropical/Tropical Moist Lowland	possible	unknown
Shrubland	Subtropical/Tropical Moist	possible	unknown
Altitude	0 - 1700 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Acridotheres tristis	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Whole (>90%)		Unknown		Past Impact
		Stresses Competition
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Felis catus	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Whole (>90%)		Unknown		Past Impact
		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
		Past, Unlikely to Return		Whole (>90%)		Unknown		Past Impact
		Stresses Reduced reproductive success, Species mortality

---

Recommended citation
BirdLife International (2024) Species factsheet: Forster's Reed-warbler Acrocephalus musae. Downloaded from https://datazone.birdlife.org/species/factsheet/forsters-reed-warbler-acrocephalus-musae 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.