EN
Mariana Swiftlet Aerodramus bartschi



Taxonomy

Taxonomic note
Aerodramus bartschi (del Hoyo and Collar 2014) was previously placed in the genus CollocaliaCollocalia inquieta (Sibley and Monroe 1990, 1993) was previously split into C. bartschi following Browning (1993) and AOU (1998) and C. inquieta following Browning (1993).

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- A2e+3e+4e A2e+3e+4e; B1ab(v)

Red List history
Year Category Criteria
2016 Endangered A2e+3e+4e
2012 Endangered A2e+3e+4e
2008 Endangered A2e; A3e; A4e
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 -
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 4,400 medium
Number of locations 6-10 -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 2500-9999 good estimated 2015
Population trend Decreasing poor suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 50-79 - - -
Decline (10 years/3 generation past and future) 50-79 - - -
Number of subpopulations 3 - - -
Largest subpopulations - - -
Generation length (yrs) 5 - - -

Population justification: The population is estimated at between 6000-7000 individuals (Johnson 2015, US Fish and Wildlife Service 2015) and so has been placed in the band 2,500-9,999.

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 over 5,000 individuals from 1985 to 2015 (US Fish & Wildlife Service 2015). The population on Guam is also believed to have increased to approximately 1500 individuals from 1983 to 2015 (A. Brooke in litt. 2006, Johnson 2015) while the population on Aguijan appears stable at around 300-400 individuals (J. Cruz et al. in litt. 2007, US Fish & Wildlife Service 2015). 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 Resident Breeding Non-breeding Passage
Guam (to USA) N Extant Yes
Northern Mariana Islands (to USA) N Extant Yes
USA I Extant Yes

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

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 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 Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Species disturbance
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Reduced reproductive success
Pollution Agricultural & forestry effluents Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Reduced reproductive success

Recommended citation
BirdLife International (2019) Species factsheet: Aerodramus bartschi. Downloaded from http://www.birdlife.org on 24/08/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 24/08/2019.