Micronesian Starling Aplonis opaca


Taxonomic note

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.
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2016 Least Concern
2012 Least Concern
2009 Least Concern
2008 Least Concern
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern
Species attributes

Migratory status not a migrant Forest dependency medium
Land mass type Average mass 83 g

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 1,730,000
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals unknown not applicable not applicable 0
Population trend unknown not applicable -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations - - -
Percentage in largest subpopulation - - -
Generation length (yrs) 4.1 - - -

Population justification: The global population size has not been quantified, but the species is reported to be numerous (Feare et al. 1998).

Trend justification: The population trend is difficult to determine because of uncertainty over the impacts of habitat modification on population sizes.

Country/territory distribution
Country/Territory Presence Origin Resident Breeding Non-breeding Passage
Guam (to USA) extant native yes
Micronesia, Federated States of extant native yes
Northern Mariana Islands (to USA) extant native yes
Palau extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Guam (to USA) Cocos Island, Guam
Guam (to USA) Guam National Wildlife Refuge
Micronesia, Federated States of Enipein Watershed
Micronesia, Federated States of Mount Winipot / Tol South
Micronesia, Federated States of Onei Island
Micronesia, Federated States of Pata Island
Micronesia, Federated States of Pilapen Kepin River Watershed
Micronesia, Federated States of Pohnpei Watershed Forest Reserve
Micronesia, Federated States of Polle Island
Micronesia, Federated States of Salapwuk
Micronesia, Federated States of South Weno Ridge
Micronesia, Federated States of Southeast Pohnpei / Nan Madol
Micronesia, Federated States of Uman Island
Micronesia, Federated States of Utwa-Walung Conservation Area
Micronesia, Federated States of Wiya Swiftlet Cave
Micronesia, Federated States of Yap Island
Micronesia, Federated States of Yela River Watershed
Northern Mariana Islands (to USA) Aguiguan Island and Naftan Rock
Northern Mariana Islands (to USA) Alamagan Island
Northern Mariana Islands (to USA) Asuncion Island
Northern Mariana Islands (to USA) Guguan Island
Northern Mariana Islands (to USA) Maug Islands
Northern Mariana Islands (to USA) Northern Saipan
Northern Mariana Islands (to USA) Rota
Northern Mariana Islands (to USA) Sarigan Island
Northern Mariana Islands (to USA) Tinian Island
Northern Mariana Islands (to USA) Topachau-Susupe-Kagman
Palau Middle Ridge, Babeldaob
Palau Ngerutechei, Babeldaob
Palau Peleliu
Palau Rock Islands
Palau Western Ridge, Babeldaob

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Subtropical/Tropical Heavily Degraded Former Forest major resident
Forest Subtropical/Tropical Dry suitable resident
Forest Subtropical/Tropical Moist Lowland major resident
Shrubland Subtropical/Tropical Dry suitable resident
Shrubland Subtropical/Tropical Moist suitable resident
Altitude   Occasional altitudinal limits  

Recommended citation
BirdLife International (2023) Species factsheet: Aplonis opaca. Downloaded from on 07/06/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from on 07/06/2023.