• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Taxonomic source(s)
Christidis, L. and Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. CSIRO Publishing, Collingwood, Australia.
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.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2022	Least Concern
2016	Near Threatened	D2
2013	Near Threatened	D2
2012	Near Threatened	D2
2008	Vulnerable	D2
2004	Vulnerable
2000	Vulnerable
1996	Vulnerable
1994	Vulnerable
1988	Lower Risk/Least Concern

Migratory status	not a migrant	Forest dependency	low
Land-mass type		Average mass	8 g

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	72 km2	medium
Area of Occupancy (breeding/resident)	72 km2	good
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	3800-8000, 5000 mature individuals	poor	estimated	2020
Population trend	unknown	medium	-	-
Generation length	2.95 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: Inside Norfolk Island National Park, 3,830 (95% CI 2,650-5,540) mature individuals were estimated in 2009 (Dutson 2013), followed by a higher estimate of 6,305 (95% CI 5,166-8,583) in October 2019. Following Nance et al. (2021), the population size of the whole island is therefore set to 3,800-8,000 mature individuals, with a best estimate of c.5,000.

Trend justification: Historically, c.1600 pairs were estimated to persist in 1988 and 1997 (Robinson 1988, 1997). A larger estimate was made in 2009, when 3,830 (95% CI 2,650-5,540) were thought to exist in the national park (Dutson 2013), while an even more recent estimate (6,305; 95% CI 5,166-8,583) from 2019 suggests the population may have increased further (Nance et al. 2021). However, each of these estimates was born from differences in survey technique, such that direct and robust comparisons are not possible. Nonetheless, a decline is considered very unlikely, and the species is probably increasing in abundance (Nance et al. 2021). 

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Norfolk Island (to Australia)	extant	native	yes

Country/Territory	IBA Name
Norfolk Island (to Australia)	Norfolk Island

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Pastureland	suitable	resident
Artificial/Terrestrial	Rural Gardens	suitable	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Shrubland	Subtropical/Tropical Moist	major	resident
Altitude	0 - 320 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Small-holder farming	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Majority (50-90%)		Negligible declines		Past Impact
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Livestock farming & ranching - Small-holder grazing, ranching or farming	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Majority (50-90%)		Negligible declines		Past Impact
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Majority (50-90%)		Negligible declines		Past Impact
		Stresses Ecosystem degradation, Ecosystem conversion
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Felis catus	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		No decline		Low Impact: 4
		Stresses Reduced reproductive success
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Rattus exulans	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		No decline		Low Impact: 4
		Stresses Reduced reproductive success
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Rattus rattus	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		No decline		Low Impact: 4
		Stresses Reduced reproductive success
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Unspecified species	Timing		Scope		Severity		Impact
		Future		Whole (>90%)		Unknown		Unknown
		Stresses Species mortality

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Recommended citation
BirdLife International (2024) Species factsheet: Norfolk Island Gerygone Gerygone modesta. Downloaded from https://datazone.birdlife.org/species/factsheet/norfolk-island-gerygone-gerygone-modesta on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 23/11/2024.