Sterna vittata

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	CHARADRIIFORMES	LARIDAE

Scientific Name:

Sterna vittata

Species Authority:

Gmelin, 1789

Common Name/s:

English	–	Antarctic Tern
French	–	Sterne couronnée

Taxonomic Notes:

The BirdLife Taxonomic Working Group is aware that phylogenetic analyses have been published which have proposed generic rearrangements which may affect this species, but prefers to wait until work by other taxonomists reveals how these changes affect the entire groups involved.

Assessment Information [top]

Red List Category & Criteria:

Least Concern ver 3.1

Year Published:

2012

Assessor/s:

BirdLife International

Reviewer/s:

Butchart, S. & Symes, A.

Contributor/s:

Justification:
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). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid 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.

History:

2009	–	Least Concern
2008	–	Least Concern
2004	–	Least Concern

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:	Native: Antarctica; Argentina; Australia; Bouvet Island; Brazil; Chile; Falkland Islands (Malvinas); French Southern Territories (the); Heard Island and McDonald Islands; New Zealand; Saint Helena, Ascension and Tristan da Cunha; South Africa; South Georgia and the South Sandwich Islands; Uruguay
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population Trend:	Decreasing

Population Trend:

Decreasing

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

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

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).

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 2012. Sterna vittata. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 26 May 2013.
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