Grey-backed Myna Acridotheres tricolor


Taxonomic note
Acridotheres melanopterus, A. tricolor and A. tertius (del Hoyo and Collar 2016) were previously lumped as Sturnus melanopterus following Sibley & Monroe (1990, 1993).

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
C2a(i) C2a(i); D A2d+3d+4d; C2a(i); D1

Red List history
Year Category Criteria
2016 Critically Endangered C2a(i)
Species attributes

Migratory status not a migrant Forest dependency Low
Land mass type Average mass -
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 2,500 medium
Number of locations 11-100 -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 50-249 poor estimated 2016
Population trend Decreasing poor inferred -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 30-49 - - -
Decline (10 years/3 generation past and future) 30-49 - - -
Number of subpopulations 2-100 - - -
Largest subpopulations 1-89 - - -
Generation length (yrs) 4.44 - - -

Population justification: The population is estimated to number fewer than 250 mature individuals in the wild, based on an assessment of recent records pertaining to this species (eBird 2016, S, Mahood in litt. 2009, Eaton et al. 2015). The maximum recent count of individuals is 37 observed together in Baluran (Robson 2016), and 25 in Alas Purwo (Eaton et al. 2015). Addition birds may be present in Meru Betiri, but no recent records have been reported (Eaton et al. 2015). Thorough survey of the remaining populations may reveal that the population is larger than estimated from the limited data available, though the population is clearly very small.

Trend justification: A very rapid decline occurred in the species in the late 20th century attributed to trapping for the cage bird trade (BirdLife International 2001) and in the past five years the species has only been reported at two sites (Eaton et al. 2015). Grey-backed Myna is not as sought after as Black-winged, but still commands a high price (S. Chng in litt. 2016) but in recent years very few have been observed during market surveys (Shepherd et al. 2015, Chng et al. 2015). From this it is inferred that numbers outside of the protected areas must be vanishingly small. Populations within the protected areas are unlikely to be safe from trapping (BirdLife International 2001, Eaton et al. 2015), though the rate of decline inferred from reported records within the last 13 years (3 generations) appears slow. But given that demand for the species in the cage-bird trade is not likely to decrease, this rate of decline is projected to continue into the future.

Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Indonesia N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Arable Land suitable resident
Artificial/Terrestrial Pastureland suitable resident
Forest Subtropical/Tropical Dry suitable resident
Savanna Dry suitable resident
Shrubland Subtropical/Tropical Dry suitable resident
Shrubland Subtropical/Tropical Moist suitable resident
Altitude 0 - 2400 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Hunting & trapping terrestrial animals Timing Scope Severity Impact
Ongoing Majority (50-90%) Rapid Declines Medium Impact: 7
Reduced reproductive success, Species mortality
Pollution Agricultural & forestry effluents Timing Scope Severity Impact
Ongoing Unknown Slow, Significant Declines Unknown
Ecosystem degradation, Reduced reproductive success, Species mortality

Recommended citation
BirdLife International (2018) Species factsheet: Acridotheres tricolor. Downloaded from on 23/09/2018. Recommended citation for factsheets for more than one species: BirdLife International (2018) IUCN Red List for birds. Downloaded from on 23/09/2018.