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

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: http://www.aerc.eu/DOCS/Bird_taxa_of_the_WP15.xls.
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. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	D2

Red List history

Year	Category	Criteria
2018	Vulnerable	D2
2016	Vulnerable	D2
2012	Vulnerable	D2
2010	Vulnerable	D2
2008	Vulnerable	D2
2005	Vulnerable
2004	Vulnerable
2000	Vulnerable
1996	Critically Endangered
1994	Critically Endangered
1988	Threatened

Migratory status	not a migrant	Forest dependency	does not normally occur in forest
Land-mass type		Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	2,620,000 km2	medium
Extent of Occurrence (non-breeding)	2,790,000 km2	medium
Area of Occupancy (breeding/resident)	1 km2	medium
Number of locations	2	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	17000-21000 mature individuals	medium	estimated	2007
Population trend	stable	not applicable	suspected	1980-2010
Generation length	15.5 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: The current population of mature females is estimated at 9,341 (95% CI: 8,587-10,113), based on census data from 2001-2002, suggesting there may be c.18,682 mature individuals, assuming an equal sex ratio. The confidence intervals for the number of mature females are doubled and rounded to provide a range estimate of 17,000-21,000 for the number of mature individuals, roughly equivalent to 25,000-32,000 individuals in total.

Trend justification: It is difficult to determine the current population trend owing to poor baseline information, the difficulties of carrying out census work and the high number of mature non-breeders in the population (Pickup 1998; Ratcliffe 1999). However, the use of a 'virtual ecologist' model on recent census data, alongside historic data, point to a stable population (Ratcliffe et al. 2008).

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Brazil	extant	vagrant			yes
St Helena (to UK)	extant	native		yes
United Kingdom	extant	vagrant			yes

Country/Territory	IBA Name
St Helena (to UK)	Boatswainbird Island
St Helena (to UK)	Letterbox Peninsula

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Marine Coastal/Supratidal	Sea Cliffs and Rocky Offshore Islands	major	breeding
Marine Neritic	Pelagic	major	resident
Marine Oceanic	Epipelagic (0-200m)	major	resident
Altitude		Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Biological resource use	Fishing & harvesting aquatic resources - Unintentional effects: (large scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Indirect ecosystem effects, Species mortality
Biological resource use	Hunting & trapping terrestrial animals - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Majority (50-90%)		Rapid Declines		Past Impact
		Stresses Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Felis catus	Timing		Scope		Severity		Impact
		Past, Likely to Return		Whole (>90%)		Rapid Declines		Past Impact
		Stresses Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Rattus rattus	Timing		Scope		Severity		Impact
		Past, Likely to Return		Whole (>90%)		Rapid Declines		Past Impact
		Stresses Reduced reproductive success

Purpose	Scale
Pets/display animals, horticulture	international

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Recommended citation
BirdLife International (2024) Species factsheet: Ascension Frigatebird Fregata aquila. Downloaded from https://datazone.birdlife.org/species/factsheet/ascension-frigatebird-fregata-aquila on 22/12/2024.
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 22/12/2024.