VU
Biak Gerygone Gerygone hypoxantha



Taxonomy

Taxonomic note
Gerygone magnirostris and G. hypoxantha (del Hoyo and Collar 2016) were previously lumped as G. magnirostris following Christidis & Boles (2008) and 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.
Morony, J. J.; Bock, W. J.; Farrand, J. 1975. Reference list of the birds of the world. Department of Ornithology, American Museum of Natural History, New York.
Morony, J. J.; Bock, W. J.; Farrand, J. 1975. Reference list of the birds of the world. Department of Ornithology, American Museum of Natural History, New York.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - C2a(ii)

Red List history
Year Category Criteria
2016 Vulnerable C2a(ii)
2012 Not Recognised
2008 Not Recognised
2007 Not Recognised
2004 Endangered
2000 Endangered
1994 Endangered
1988 Threatened
Species attributes

Migratory status not a migrant Forest dependency Medium
Land mass type Average mass 7 g
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 3,600
Number of locations 11-100 -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 2500-9999 poor inferred 2016
Population trend Decreasing 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) 1-9 - - -
Decline (10 years/3 generation past and future) 1-9 - - -
Number of subpopulations 1 - - -
Percentage in largest subpopulation 100 - - -
Generation length (yrs) 5.5 - - -

Population justification: A population estimate of 2,500-9,999 mature individuals has been made based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied.

Trend justification: This population is suspected to be in slow decline owing to ongoing habitat destruction (Gregory 2016).


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 Biak
Indonesia Supiori

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Dry suitable resident
Forest Subtropical/Tropical Mangrove Vegetation Above High Tide Level major resident
Forest Subtropical/Tropical Moist Lowland suitable resident
Shrubland Subtropical/Tropical Moist suitable resident
Altitude   Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Shifting agriculture Timing Scope Severity Impact
Ongoing Low Impact: 3
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Low Impact: 3
Stresses
Ecosystem degradation, Ecosystem conversion

Recommended citation
BirdLife International (2021) Species factsheet: Gerygone hypoxantha. Downloaded from http://www.birdlife.org on 28/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 28/10/2021.