Justification This species has an extremely 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 appears to be fluctuating, and hence the species does not 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.

Family/Sub-family Laridae

Species name author Latham, 1787

Taxonomic source(s) AERC TAC (2003), AOU checklist (1998 + supplements), Cramp and Simmons (1977-1994), Dowsett and Forbes-Watson (1993), SACC (2005 + updates), Sibley and Monroe (1990, 1993), Stotz et al. (1996)

Synonyms Thalasseus sandvicensis AOU checklist (1998 + supplements), Thalasseus sandvicensis Stotz et al. (1996)

Taxonomic note 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.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

490,000 - 640,000

unset

1,210,000 km²

No

Range & population The Sandwich Tern can be found in Europe, Africa, western Asia, and the southern Americas. It breeds seasonally on the coast of much of Europe east to the Caspian Sea, wintering from the Caspian, Black and Mediterranean Seas to the coasts of western and southern Africa, and from the south Red Sea to north-west India and Sri Lanka. In the Americas, it breeds from Virginia to Texas (USA), on the coasts of the Yucatan Peninsula, Lesser Antilles, Venezuala, French Guiana, eastern Brazil and Argentina. It winters from Texas, USA down to southern Argentina, in the Greater Antilles and from southern Mexico down to northern Chile¹.

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: Behaviour This species is migratory, undergoing post-breeding dispersive movements north and south to favoured feeding grounds before migrating southward¹. It breeds in dense colonies with other terns or Black-headed Gulls Larus ridibundus¹ and is gregarious throughout the year, often forming feeding flocks where prey is abundant or concentrated (although it may also feed solitarily)². Habitat Breeding During the breeding season the species forms colonies on sandy islands, rocky calcareous islets, sand-spits, sand-dunes, shingle beaches and extensive deltas² with immediate access to clear waters with shallow sandy substrates rich in surface-level fish². It shows a preference for raised, open, unvegetated sand, gravel, mud or bare coral substrates for nesting¹. Non-breeding Outside of the breeding season the species frequents sandy or rocky beaches, mudflats fringed by mangroves, estuaries, harbours and bays, often feeding over inlets and at sea¹. Diet Its diet consists predominantly of surface-dwelling marine fish² 9-15 cm long¹ as well as small shrimps, marine worms and shorebird nestlings¹. Breeding site The nest is a shallow scrape on raised, open, unvegetated sand, gravel, mud or bare coral substrates preferably far from upright vegetation¹ on sandy islands, rocky calcareous islets, sand-spits, sand-dunes and shingle beaches². The species forms very dense colonies during the breeding season in which the eggs of neighbouring pairs may only be 20 cm apart¹. Management information The species responds favourably to habitat management such as vegetation clearance, and can be readily attracted to suitable nesting habitats by the use of decoys¹. Breeding pairs are also known to be attracted to coastal locations where artificial nesting sites have been constructed (e.g. beaches of bare shingle and islands or rafts covered with sparse vegetation)⁴. A conservation scheme for the protection of gull and tern breeding colonies in coastal lagoons and deltas (e.g. Po Delta, Italy) involves protection from human disturbance, prevention of erosion of islet complexes, habitat maintenance and the creation of new islets for nest sites⁵. The scheme particularly specifies that bare islets with 30-100 % cover of low vegetation (sward heights less than 20 cm) should be maintained or created as nesting sites⁵.

Threats The species is particularly vulnerable to human disturbance¹ (e.g. from tourists) especially near breeding colonies on beaches early in the breeding season⁶. It is also sensitive to disturbance from coastal wind farms (wind turbines)³. It is threatened by the loss or degradation of its favoured breeding habitats through inundation, wind-blown sand and erosion¹, and has suffered previous local declines from to exposure to bioaccumulated organochlorine pollutants in marine fish^{1, 7}. Egg collecting at breeding colonies also poses a threat to the species throughout the tropics¹. Utilisation This species is hunted in West Africa during the winter¹.

References 1. del Hoyo et al. (1996). 2. Snow and Perrins (1998). 3. Garthe and Huppop (2004). 4. Burgess and Hirons (1992). 5. Fasola and Canova (1996). 6. Bourne and Smith (1974). 7. Koeman et al. (1967).

Further web sources of information

Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)

Text account compilers Stuart Butchart (BirdLife International), Rob Calvert (BirdLife International), Jonathan Ekstrom (BirdLife International), Lucy Malpas (BirdLife International)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International)

Recommended citation BirdLife International (2010) Species factsheet: Sterna sandvicensis. Downloaded from http://www.birdlife.org on 6/9/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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