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Mariana Swiftlet Aerodramus bartschi

IUCN Red List Criteria

Critically Endangered  
Endangered A2e+3e+4e 
Vulnerable A2e+3e+4e;B1ab(v) 

IUCN Red List history

Year Category
2012 Endangered
2008 Endangered
2004 Endangered
2000 Endangered
1994 Not Recognised
1988 Not Recognised

Species attributes

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

Distribution

  Estimate Data quality
Extent of Occurrence breeding/resident (km2) 730 medium
Number of locations 6-10 -
Fragmentation -

Population & trend

  Estimate Data quality Derivation Year of estimate
No. of mature individuals 2100-2300 good Estimated 1999
Population trend Decreasing poor -
Number of subpopulations 3 - - -
Largest subpopulation 1001-3100 - - -
Generation length (yrs) 5 - - -
Population justification: The population estimate of 3,200-3,500 individuals is derived from G. Wiles in litt. and Wiles & Woodside (1999). This is roughly equivalent to 2,100-2,300 mature individuals.
Trend justification: Population estimates have fluctuated over the last two decades but appear to be increasing. Recent population estimates on Saipan indicate that the population has increased to approximately 5,400 individuals from 1985 to 2005 (J. Cruz et al. in litt. 2007). The population on Guam is also believed to have increased to approximately 900 individuals from 1983 to 2006 (A. Brooke in litt. 2006) while the population on Aguijan appears stable at around 400 individuals based on 2002 surveys (J. Cruz et al. in litt. 2007). However, on Saipan, the species's stronghold, brown tree snake Boiga irregularis is in the process of becoming established (Rodd and Savidge 2007), which  is expected to cause a very rapid decline.

Country/Territory distribution

Country/Territory Occurrence status Presence Breeding Non-breeding Passage Resident
Guam (to USA) Native Extant Yes      
Northern Mariana Islands (to USA) Native Extant Yes      
USA Introduced Extant Yes      

Important Bird Areas where this species has triggered the IBA criteria

Country/Territory IBA Name IBA link
Guam (to USA) Guam National Wildlife Refuge site factsheet
Guam (to USA) Mahlac Caves site factsheet
Northern Mariana Islands (to USA) Aguiguan Island and Naftan Rock site factsheet
Northern Mariana Islands (to USA) Northern Saipan site factsheet
Northern Mariana Islands (to USA) Topachau-Susupe-Kagman site factsheet

Habitats & altitude

Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Pastureland suitable resident
Caves and Subterranean Habitats (non-aquatic) Caves major breeding
Forest Subtropical/Tropical Mangrove Vegetation Above High Tide Level suitable resident
Forest Subtropical/Tropical Moist Lowland major resident
Altitude 0 - 600 m Occasional altitudinal limits  

Threats & impact

Threat (level 1) Threat (level 2) Impact and Stresses
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species disturbance
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases / Brown Tree Snake (Boiga irregularis) Timing Scope Severity Impact
Ongoing Majority (50-90%) Rapid Declines Medium Impact: 7
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases / Goat (Capra hircus) Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Decline Low Impact: 5
Stresses
Species disturbance
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases / Unspecified cockroach (Blatodea) Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Decline Low Impact: 5
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases / Unspecified wasps (Vespula spp.) Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Decline Low Impact: 5
Stresses
Reduced reproductive success
Pollution Agricultural & forestry effluents / Herbicides and pesticides Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Reduced reproductive success

Recommended citation
BirdLife International (2014) Species factsheet: Aerodramus bartschi. Downloaded from http://www.birdlife.org on 20/12/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 20/12/2014.

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 Endangered
Family Apodidae (Swifts)
Species name author Mearns, 1909
Population size 2100-2300 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 730 km2
Country endemic? No
Links to further information
- Summary information on this species