CR
Nias Hill Myna Gracula robusta



Taxonomy

Taxonomic note

Gracula religiosa, G. venerata, G. robusta and G. indica (del Hoyo and Collar 2016) were previously lumped as G. religiosa following AOU (1998 and supplements) and Sibley and 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
A2bd+3d+4bd; C2a(ii) A2bd+3d+4bd; B2ab(i,ii,iii,iv,v); C2a(i); D A2bd+3d+4bd; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(i); D1

Red List history
Year Category Criteria
2020 Critically Endangered A2bd+3d+4bd; C2a(ii)
2018 Critically Endangered A2bd+3d+4bd; C2a(i)
2016 Critically Endangered A2bd+3d+4bd; C2a(i)
Species attributes

Migratory status not a migrant Forest dependency Medium
Land mass type Average mass 192 g
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 12,100 medium
Number of locations 3 -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 160-265 medium estimated 2020
Population trend Decreasing estimated -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 80-100 - - -
Decline (10 years/3 generation past and future) 80-100 - - -
Number of subpopulations 2 - - -
Percentage in largest subpopulation 1-89 - - -
Generation length (yrs) 5.1 - - -

Population justification: There are potentially two populations, though there are only two recent records of wild individuals on one island and the situation there may be complicated by possible releases that may have taken place. Any wild population on this island numbers fewer than 50 mature individuals. The species has recently been found to still occur at one other island, where the species is currently well-protected and estimated at at least 250 individuals (F. Rheindt in litt. 2020). Overall the population is estimated at between 250-400 individuals, roughly equivalent to 160-270 mature individuals. Concern over poaching from this island is very high, although rangers have been in place supported by a regional NGO to reduce the risk (F. Rheindt in litt. 2020). However on another island within the former range, the species is apparently now extinct, having disappeared following a period of intense trapping on the island, which principally targeted White-rumped Shama (Eaton et al. 2016).

Trend justification: This species is seriously impacted by capture for the domestic cage bird trade. On one island it was reported to have become extinct within a very short period of time after 'hundreds' of trappers came to the island targeting White-rumped Shama Kittacinlca malabarica at some time in 2010 (Eaton et al. 2015). As such, the species is considered to be undergoing an extremely rapid decline. Further reports of confiscations of apparently wild-caught individuals (KSDAE 2018) indicate that this is likely to be continuing.


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
Indonesia Pulau Nias

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Plantations suitable resident
Forest Subtropical/Tropical Mangrove Vegetation Above High Tide Level suitable resident
Forest Subtropical/Tropical Moist Lowland major resident
Altitude 0 - 100 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Ongoing Whole (>90%) Very Rapid Declines High Impact: 9
Stresses
Species disturbance, Hybridisation, Species mortality
Invasive and other problematic species, genes & diseases Problematic native species/diseases - Gracula religiosa Timing Scope Severity Impact
Future Majority (50-90%) Rapid Declines Low Impact: 5
Stresses
Hybridisation, Reduced reproductive success

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Pets/display animals, horticulture - - International Non-trivial Recent

Recommended citation
BirdLife International (2021) Species factsheet: Gracula robusta. Downloaded from http://www.birdlife.org on 15/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 15/10/2021.