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

Taxonomic note

Crossleyia tenebrosa (del Hoyo and Collar 2016) was previously listed as Bernieria tenebrosa.

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
-	-	-

Red List history

Year	Category	Criteria
2020	Data Deficient
2016	Vulnerable	B1ab(i,ii,iii,v)
2012	Vulnerable	B1ab(i,ii,iii,v)
2008	Vulnerable	B1a+b(i,ii,iii,v)
2004	Vulnerable
2000	Vulnerable
1996	Endangered
1994	Endangered
1988	Threatened

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	50,600 km2	medium

	Estimate	Data quality	Derivation	Year of estimate
Population size	unknown	-	unknown	-
Population trend	decreasing	medium	suspected	-
Generation length	2.7 years	-	-	-

Population justification: There have been no reliable sightings of this species for the last 20 years (M. Mills in litt. 2020), and as such the population size of this species is now unknown.

Trend justification: The species's population is suspected to be declining in line with the clearance and degradation of lowland rainforest in eastern Madagascar. The likely rate of decline, however, has not been estimated.

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

Country/Territory	IBA Name
Madagascar	Marojejy National Park
Madagascar	Zahamena National Park and Strict Reserve

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude	200 - 950 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Shifting agriculture	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
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

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Recommended citation
BirdLife International (2024) Species factsheet: Dusky Tetraka Crossleyia tenebrosa. Downloaded from https://datazone.birdlife.org/species/factsheet/dusky-tetraka-crossleyia-tenebrosa 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.