Sterna vittata 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Laridae

Scientific Name: Sterna vittata Gmelin, 1789
Common Name(s):
English Antarctic Tern
French Sterne couronnée
Taxonomic Source(s): Turbott, E.G. 1990. Checklist of the Birds of New Zealand. Ornithological Society of New Zealand, Wellington.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Butchart, S., Calvert, R., Ekstrom, J., Malpas, L. & Symes, A.
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend is unknown, but is not believed to be declining sufficiently rapidly to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Previously published Red List assessments:

Geographic Range [top]

Range Description:The Antarctic Tern can be found breeding on a large number of islands in the Southern Oceans and off the coast of Antarctica. Some birds from the south of its range have been found wintering on the coast of Argentina and South Africa1.

Countries occurrence:
Antarctica; Argentina; Australia; Bouvet Island; Brazil; Chile; Falkland Islands (Malvinas); French Southern Territories; Heard Island and McDonald Islands; New Zealand; Saint Helena, Ascension and Tristan da Cunha; South Africa; South Georgia and the South Sandwich Islands; Uruguay
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:39500000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Upper elevation limit (metres):100
Range Map:Click here to open the map viewer and explore range.

Population [top]


Trend Justification:  The population of S. v. sanctipauli is decreasing, but trends for the remainder of populations, and therefore the overall trend, is unknown (Wetlands International 2006).
Current Population Trend:Unknown
Additional data:
Continuing decline of mature individuals:Unknown
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:Behaviour Breeding populations in the southern part of this species's range are migratory, post-breeding flocks migrating long distances to winter off the southern coasts of South America and South Africa (del Hoyo et al. 1996). Those populations that winter in South America arrive from mid April and depart again from mid-October, during which time the adults moult their flight feathers (del Hoyo et al. 1996). Some populations around Antarctica remain close to their breeding grounds all year round however and moult on ice-floes or icebergs on open water (del Hoyo et al. 1996). The species breeds between November and December although the exact timing varies depending on climate and food availability (del Hoyo et al. 1996). It usually nests in small loose colonies of 5-20 pairs although it may often nest singly and has been known to nest in larger colonies of up to 1,000 pairs (del Hoyo et al. 1996). It forages in inshore waters singly or in small flocks (Urban et al. 1986, del Hoyo et al. 1996) and in the winter communal roosts of 10-1,200 individuals often form (Urban et al. 1986). Habitat Breeding The species breeds on rocky areas very near the coast or a short distance inland (Higgins and Davies 1996), showing a strong preference for nesting sites that are inaccessible to ground predators (del Hoyo et al. 1996). Suitable nesting habitats include vegetated or unvegetated rocky islets, offshore stacks, coastal cliffs, gravel, rocky and sandy beaches and sparse scrubland (del Hoyo et al. 1996). The species forages in inshore waters up to 200 m from the shore and in coves, bays, inlets, harbours and off estuaries, especially where there are large forests of kelp (Higgins and Davies 1996). Non-breeding Outside of the breeding season the species moves to the nearest area of open water or to pelagic zones far from land (Higgins and Davies 1996) where it forms communal roosts on ice-floes and icebergs (Higgins and Davies 1996) and forages in patches of unfrozen inshore water or in open water along the edge of ice. More migratory populations also winter off the temperate southern coasts of South America and South Africa with adjacent cold water currents (Higgins and Davies 1996), inhabiting rocky headlands and beaches (del Hoyo et al. 1996). Diet Its diet consists predominantly of small fish although it also takes polychaetes (del Hoyo et al. 1996), molluscs (Higgins and Davies 1996) (e.g. limpets) (del Hoyo et al. 1996), crustaceans (e.g. euphausiids and amphipods), insects (del Hoyo et al. 1996) and algae (Higgins and Davies 1996). Breeding site The species nests in natural depressions in rock or in shallow scrapes in soil, sand or vegetation (del Hoyo et al. 1996) that may be positioned on ledges or crevices of sheer cliffs, boulders at the base of cliffs, headlands, stacks, rocky islets, ridges, spits and peninsulas, rock fields by freshwater, and beaches of gravel, coarse shingle and sand (Higgins and Davies 1996).
Systems:Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):11
Movement patterns:Full Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s): The species is vulnerable to human disturbance and to the introduction of ground-based predators on offshore islands including domestic or feral cats Felis catus (del Hoyo et al. 1996, Hockey et al. 2005) and rats (del Hoyo et al. 1996).

Citation: BirdLife International. 2016. Sterna vittata. The IUCN Red List of Threatened Species 2016: e.T22694635A93460313. . Downloaded on 23 May 2018.
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