DD
Dusky Tetraka Crossleyia tenebrosa



Taxonomy

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.

IUCN Red List criteria met and history
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
Species attributes

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

Estimate Data quality
Extent of Occurrence (breeding/resident) 50,600 km2 medium
Population
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 distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Madagascar extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Madagascar Marojejy National Park
Madagascar Zahamena National Park and Strict Reserve

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

Threats & impact
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

Recommended citation
BirdLife International (2024) Species factsheet: Dusky Tetraka Crossleyia tenebrosa. Downloaded from https://datazone.birdlife.org/species/factsheet/dusky-tetraka-crossleyia-tenebrosa on 23/12/2024.
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 23/12/2024.