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VU
Dusky Tetraka Bernieria tenebrosa

IUCN Red List Criteria

Critically Endangered  
Endangered  
Vulnerable B1ab(i,ii,iii,v) 

IUCN Red List history

Year Category
2012 Vulnerable
2008 Vulnerable
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 -

Distribution

  Estimate Data quality
Extent of Occurrence breeding/resident (km2) 16,000 medium
Number of locations -
Fragmentation -

Population & trend

  Estimate Data quality Derivation Year of estimate
No. of mature individuals 1500-7000 poor Estimated 2000
Population trend Decreasing medium -
Number of subpopulations 2-100 - - -
Largest subpopulation 1001-9000 - - -
Generation length (yrs) 3.6 - - -
Population justification: The population size is preliminarily estimated to fall into the band 2,500-9,999 individuals. This equates to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals.
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 Occurrence status Presence Breeding Non-breeding Passage Resident
Madagascar Native Extant       Yes

Important Bird Areas where this species has triggered the IBA criteria

Country/Territory IBA Name IBA link
Madagascar Marojejy National Park site factsheet
Madagascar Zahamena National Park site factsheet
Madagascar Zahamena-Mantadia SAPM site factsheet

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 Decline 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 Decline Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion

Recommended citation
BirdLife International (2014) Species factsheet: Bernieria tenebrosa. Downloaded from http://www.birdlife.org on 16/09/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/09/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Key facts
Current IUCN Red List category Vulnerable
Family Sylviidae (Old World warblers)
Species name author (Stresemann, 1925)
Population size 1500-7000 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 16,000 km2
Country endemic? Yes
Links to further information
- Summary information on this species