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

Taxonomic source(s)
Allen, D.; Oliveros, C.; Española, C.; Broad, G.; Gonzalez, J.C. T. 2004. A new species of Gallirallus from Calayan island, Philippines. Forktail 20: 1-7.
Allen, D.; Oliveros, C.; Española, C.; Broad, G.; Gonzalez, J.C. T. 2004. A new species of Gallirallus from Calayan island, Philippines. Forktail 20: 1-7.
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	D2

Red List history

Year	Category	Criteria
2016	Vulnerable	D2
2015	Vulnerable	D2
2012	Vulnerable	D2
2011	Vulnerable	D1; D2
2008	Vulnerable	D1; D2
2005	Vulnerable
2004	Not Recognised
2000	Not Recognised
1994	Not Recognised
1988	Not Recognised

Migratory status	not a migrant	Forest dependency	high
Land-mass type		Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	70 km2	good
Area of Occupancy (breeding/resident)	90 km2	good
Number of locations	1	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	2500-4300 mature individuals	good	estimated	2012
Population trend	stable	medium	suspected	-
Rate of change over the past 10 years/3 generations (longer of the two periods)	0%	-	-	-
Generation length	3.4 years	-	-	-

Population justification: Allen et al. (2004), estimated 100-200 pairs. It has since been found to be locally common, with an estimated area of occupancy of 36 km². However recent species distribution modelling estimated its area of occupancy at 90.2 km² (C. Layusa and C. Oliveros in litt. 2012). These latest estimates based on species distribution modelling and known densities put the population size at 3,800–6,500 individuals (C. Layusa and C. Oliveros in litt. 2012), equating to 2,500-4,300 mature individuals.

Trend justification: The population is suspected to be stable in the absence of evidence for any substantial declines or threats.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Philippines	extant	native		yes

Country/Territory	IBA Name

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude		Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Biological resource use	Hunting & trapping terrestrial animals - Unintentional effects (species is not the target)	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Negligible declines		Low Impact: 5
		Stresses Species mortality
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Canis familiaris	Timing		Scope		Severity		Impact
		Future		Majority (50-90%)		Rapid Declines		Low Impact: 5
		Stresses Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Felis catus	Timing		Scope		Severity		Impact
		Future		Majority (50-90%)		Rapid Declines		Low Impact: 5
		Stresses Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Named species	Timing		Scope		Severity		Impact
		Future		Majority (50-90%)		Rapid Declines		Low Impact: 5
		Stresses Reduced reproductive success
Residential & commercial development	Tourism & recreation areas	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem conversion
Transportation & service corridors	Roads & railroads	Timing		Scope		Severity		Impact
		Future		Majority (50-90%)		Slow, Significant Declines		Low Impact: 4
		Stresses Ecosystem degradation

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Recommended citation
BirdLife International (2024) Species factsheet: Calayan Rail Aptenorallus calayanensis. Downloaded from https://datazone.birdlife.org/species/factsheet/calayan-rail-aptenorallus-calayanensis on 20/12/2024.
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 20/12/2024.