|Scientific Name:||Thalasseus sandvicensis|
|Species Authority:||(Latham, 1787)|
Sterna sandvicensis Latham, 1787
Thalasseus sandvicensis AOU checklist (1998 + supplements)
Thalasseus sandvicensis Stotz et al., 1996
|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.|
|Taxonomic Notes:||Thalasseus sandvicensis (del Hoyo and Collar 2014) was previously placed in the genus Sterna.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Reviewer(s):||Butchart, S. & Symes, A.|
|Facilitator/Compiler(s):||Ashpole, J, Butchart, S., Calvert, R., Ekstrom, J., Malpas, L.|
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.
|Previously published Red List assessments:|
|Range Description:||This species 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 (U.S.A.), on the coasts of the Yucatan Peninsula, Lesser Antilles, Venezuela, 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 Chile (del Hoyo et al. 1996).|
Native:Albania; Algeria; Angola (Angola); Anguilla; Antigua and Barbuda; Argentina; Aruba; Azerbaijan; Bahamas; Bahrain; Barbados; Belgium; Belize; Benin; Bonaire, Sint Eustatius and Saba; Brazil; Bulgaria; Cameroon; Cape Verde; Cayman Islands; Chile; Colombia; Congo; Congo, The Democratic Republic of the; Costa Rica; Côte d'Ivoire; Croatia; Cuba; Curaçao; Cyprus; Denmark; Dominica; Dominican Republic; Ecuador; Egypt; El Salvador; Equatorial Guinea; Eritrea; Estonia; France; French Guiana; Gabon; Gambia; Germany; Ghana; Gibraltar; Greece; Grenada; Guadeloupe; Guatemala; Guinea; Guinea-Bissau; Guyana; Haiti; India; Iran, Islamic Republic of; Iraq; Ireland; Israel; Italy; Jamaica; Jordan; Kazakhstan; Kenya; Kuwait; Latvia; Lebanon; Liberia; Libya; Macedonia, the former Yugoslav Republic of; Malta; Martinique; Mauritania; Mexico; Montserrat; Morocco; Mozambique; Namibia; Netherlands; Nicaragua; Nigeria; Norway; Oman; Pakistan; Palestinian Territory, Occupied; Panama; Peru; Poland; Portugal; Puerto Rico; Qatar; Romania; Russian Federation; Saint Barthélemy; Saint Kitts and Nevis; Saint Lucia; Saint Vincent and the Grenadines; Sao Tomé and Principe; Saudi Arabia; Senegal; Sierra Leone; Slovenia; South Africa; Spain; Sri Lanka; Sudan; Suriname; Sweden; Switzerland; Syrian Arab Republic; Tanzania, United Republic of; Togo; Trinidad and Tobago; Tunisia; Turkey; Turkmenistan; Turks and Caicos Islands; Ukraine; United Arab Emirates; United Kingdom; United States; Uruguay; Venezuela, Bolivarian Republic of; Virgin Islands, British; Virgin Islands, U.S.; Western Sahara; Yemen
Vagrant:Bermuda; Bosnia and Herzegovina; Czech Republic; Djibouti; Ethiopia; Falkland Islands (Malvinas); Faroe Islands; Finland; Hungary; Iceland; Montenegro; Saint Pierre and Miquelon; Serbia (Serbia); Seychelles; Slovakia; Somalia; Svalbard and Jan Mayen
Present - origin uncertain:Honduras; Saint Martin (French part); Sint Maarten (Dutch part)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The global population is estimated at 490,000-640,000 individuals (Wetlands International 2015). The European population is estimated at 79,900-148,000 pairs, which equates to 160,000-295,000 mature individuals (BirdLife International 2015).|
Trend Justification: The overall population trend is fluctuating, although some populations are stable, others have unknown trends (Wetlands International 2015). This species has undergone a small or statistically insignificant increase over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007). Note, however, that these surveys cover less than 50% of the species's range in North America. The European population is also estimated to be fluctuating (BirdLife International 2015).
|Current Population Trend:||Stable|
|Habitat and Ecology:||Behaviour This species is migratory, undergoing post-breeding dispersive movements north and south to favoured feeding grounds before migrating southward (del Hoyo et al. 1996). It breeds in dense colonies with other terns or Black-headed Gulls Larus ridibundus (del Hoyo et al. 1996) and is gregarious throughout the year, often forming feeding flocks where prey is abundant or concentrated (although it may also feed solitarily) (Snow and Perrins 1998). Habitat Breeding During the breeding season the species forms colonies on sandy islands, rocky calcareous islets, sand-spits, sand-dunes, shingle beaches and extensive deltas (Snow and Perrins 1998) with immediate access to clear waters with shallow sandy substrates rich in surface-level fish (Snow and Perrins 1998). It shows a preference for raised, open, unvegetated sand, gravel, mud or bare coral substrates for nesting (del Hoyo et al. 1996). 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 sea (del Hoyo et al. 1996). Diet Its diet consists predominantly of surface-dwelling marine fish (Snow and Perrins 1998) 9-15 cm long (del Hoyo et al. 1996) as well as small shrimps, marine worms and shorebird nestlings (del Hoyo et al. 1996). Breeding site The nest is a shallow scrape on raised, open, unvegetated sand, gravel, mud or bare coral substrates preferably far from upright vegetation (del Hoyo et al. 1996) on sandy islands, rocky calcareous islets, sand-spits, sand-dunes and shingle beaches (Snow and Perrins 1998). The species forms very dense colonies during the breeding season in which the eggs of neighbouring pairs may only be 20 cm apart (del Hoyo et al. 1996). 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 decoys (del Hoyo et al. 1996). 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) (Burgess and Hirons 1992). 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 sites (Fasola and Canova 1996). 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 sites (Fasola and Canova 1996).|
|Continuing decline in area, extent and/or quality of habitat:||Unknown|
|Generation Length (years):||10.8|
|Movement patterns:||Full Migrant|
|Congregatory:||Congregatory (and dispersive)|
|Major Threat(s):||The species is particularly vulnerable to human disturbance (del Hoyo et al. 1996) (e.g. from tourists) especially near breeding colonies on beaches early in the breeding season (Bourne and Smith 1974). It is also sensitive to disturbance from coastal wind farms (wind turbines) (Garthe and Huppop 2004). It is threatened by the loss or degradation of its favoured breeding habitats through inundation, wind-blown sand and erosion (del Hoyo et al. 1996), and has suffered previous local declines from to exposure to bioaccumulated organochlorine pollutants in marine fish (Koeman et al. 1967, del Hoyo et al. 1996). Egg collecting at breeding colonies also poses a threat to the species throughout the tropics (del Hoyo et al. 1996). Other serious threats udentified within the species's European range include recreational disturbance, coastal developments, pollution, land-use affecting vegetation and predation (Garthe and Flore 2007). Utilisation This species is hunted in West Africa during the winter (del Hoyo et al. 1996).|
Conservation Actions Underway
The following information refers to the species's European range only: CMS Appendix II. EU Birds Directive Annex I. Bern Convention Appendix II. A conservation scheme for the protection of gull and tern breeding colonies in coastal lagoons and deltas (Po Delta, Italy) involves protection from human disturbance, prevention of erosion of islet complexes, habitat maintenance and the creation of new islets for nest sites (Fasola and Canova 1996). 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 sites (Fasola and Canova 1996).
Conservation Actions Proposed
The following information refers to the species's European range only: The species responds favourably to habitat management such as vegetation clearance, and can be readily attracted to suitable nesting habitats by the use of decoys (del Hoyo et al. 1996). 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) (Burgess and Hirons 1992).
|Citation:||BirdLife International. 2016. Thalasseus sandvicensis. The IUCN Red List of Threatened Species 2016: e.T22694591A86794684.Downloaded on 26 May 2017.|
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