Atlantic White Tern (Gygis alba) - BirdLife species factsheet

Atlantic White Tern Gygis alba

Current view: Data table and detailed info

Taxonomy

Taxonomic note
Gygis alba previously (del Hoyo and Collar 2014) lumped G. alba and G. candida but latter now split as separate species (which see for details). Monotypic.

Taxonomic source(s)
Handbook of the Birds of the World and BirdLife International. 2022. Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 7. Available at: https://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v7_Dec22.zip.

IUCN Red List criteria met and history

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2022	Least Concern
2016	Not Recognised
2012	Not Recognised
2008	Not Recognised
2004	Not Recognised
2000	Not Recognised
1994	Not Recognised
1988	Not Recognised

Species attributes

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

Range

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	3,476,000 km²
Extent of Occurrence (non-breeding)	5,732,000 km²
Severely fragmented?	no	-

Population

	Estimate	Data quality	Derivation	Year of estimate
Population size	20000-49999 mature individuals	medium	estimated	2022
Population trend	stable	-	suspected	-
Generation length	11.4 years	-	-	-

Population justification: The population size of Atlantic Gygis populations (here separated as a monotypic species) has not been accurately estimated, although is suspected to number c.25,000-49,999 mature individuals following Wetlands International (2022).

Trend justification: No trend data for this species are available (Wetlands International 2022) although it is suspected here to be stable in the absence of threats.

Country/territory distribution

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

Important Bird and Biodiversity Areas (IBA)

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

Habitats & altitude

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Marine Coastal/Supratidal	Sea Cliffs and Rocky Offshore Islands	major	resident
Marine Neritic	Pelagic	major	resident
Altitude	0 - 50 m	Occasional altitudinal limits

Recommended citation
BirdLife International (2024) Species factsheet: Atlantic White Tern Gygis alba. Downloaded from https://datazone.birdlife.org/species/factsheet/atlantic-white-tern-gygis-alba on 22/11/2024.
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 22/11/2024.