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

Taxonomic note
Aerodramus sawtelli (del Hoyo and Collar 2014) was previously placed in the genus Collocalia.

Taxonomic source(s)
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
-	-	D1+2

Red List history

Year	Category	Criteria
2020	Vulnerable	D1+2
2016	Vulnerable	D1+2
2012	Vulnerable	D1+2
2008	Vulnerable	D1; D2
2004	Vulnerable
2000	Vulnerable
1996	Vulnerable
1994	Vulnerable
1988	Threatened

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	31 km2	medium
Area of Occupancy (breeding/resident)	8 km2
Area of Occupancy (non-breeding)	31 km2
Number of locations	2	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	340-400 mature individuals	good	estimated	1995
Population trend	stable	poor	suspected	1998-2008
Generation length	2.58 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: In 1987-1988, a detailed survey recorded 190 active nests in two caves (74 in Anatakitaki and 116 in Vaitupurangi), leading to an estimated population size of 380 mature individuals (148 adults in Anatakitaki cave and 232 individuals in Vaitupurangi; Tarburton 1990). In 1989 the population in Anatakitaki cave was estimated at 163-241 individuals (Fullard et al. 2010). In 1994 and 1995, further surveys were conducted and, although the numbers of active nests in each cave varied from year to year, the totals were stable at 172 (82 in Anatakitaki and 90 in Vaitupurangi) and 175 (69 and 106 respectively; McCormack 1997, R. Dobbs and G. McCormack unpubl. data in Fullard et al. 2010). The number of mature individuals is therefore estimated to number 340-400.

Trend justification: Local knowledge suggests the species was higher in numbers decades ago, with the species reported as resembling swarms of butterflies (Rongo and Dyer 2014). When it was collected in 1973 from the Anatakitaki Cave there were c.60 nests and local inhabitants reported that there were a few smaller colonies elsewhere on the island (Holyoak 1974). In 1987-1988, a detailed survey recorded 380 mature individuals (148 adults in Anatakitaki cave and 232 individuals in Vaitupurangi; Tarburton 1990). In 1989 the population in Anatakitaki cave was estimated at 163-241 individuals (Fullard et al. 2010). In 1994 and 1995, further surveys were conducted and, although the numbers of active nests in each cave varied from year to year, the totals were stable at 172 (82 in Anatakitaki and 90 in Vaitupurangi) and 175 (69 and 106 respectively; McCormack 1997, R. Dobbs and G. McCormack unpubl. data in Fullard et al. 2010). In the absence of further evidence, the population is assumed to remain stable.

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

Country/Territory	IBA Name
Cook Islands	Atiu

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Plantations	suitable	resident
Caves and Subterranean Habitats (non-aquatic)	Caves	major	resident
Forest	Subtropical/Tropical Moist Lowland	suitable	resident
Shrubland	Subtropical/Tropical Moist	major	resident
Altitude		Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Human intrusions & disturbance	Recreational activities	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Negligible declines		Low Impact: 5
		Stresses Species disturbance
Invasive and other problematic species, genes & diseases	Problematic native species/diseases - Birgus latro	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Negligible declines		Low Impact: 5
		Stresses Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases	Problematic native species/diseases - Discoplax longipes	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Negligible declines		Low Impact: 5
		Stresses Reduced reproductive success, Species mortality

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Recommended citation
BirdLife International (2024) Species factsheet: Atiu Swiftlet Aerodramus sawtelli. Downloaded from https://datazone.birdlife.org/species/factsheet/atiu-swiftlet-aerodramus-sawtelli 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.