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NR
 Sterna nilotica

This taxon is Not Recognised as a species by BirdLife International.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: #http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls#.
Christidis, L.; Boles, W. E. 2008. Systematics and taxonomy of Australian birds. CSIRO Publishing, Collingwood, Australia.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
SACC. 2006. A classification of the bird species of South America. Available at: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.html#.
Turbott, E. G. 1990. Checklist of the birds of New Zealand. Ornithological Society of New Zealand, Wellington.

Taxonomic note
Gelochelidon nilotica and G. macrotarsa (del Hoyo and Collar 2014) were previously placed in the genus Sterna and lumped as S. nilotica following Sibley and Monroe (1990, 1993).

Synonym(s)
Gelochelidon nilotica Cramp and Simmons (1977-1994), Gelochelidon nilotica Christidis and Boles (2008), Gelochelidon nilotica Stotz et al. (1996), Gelochelidon nilotica AOU checklist (1998 + supplements), Gelochelidon nilotica Turbott (1990)

Distribution and population
The Gull-billed tern breeds in warmer parts of the world in southern Europe, very small isolated population in northern Germany and Denmark, temperate and eastern Asia, both coasts of central and southern North America, the north-west and eastern coasts of South America and Australia. Post-breeding dispersal expands its range to include much of south Asia, Central America, New Zealand and parts of central Africa (del Hoyo et al. 1996).

Ecology
Behaviour Northern breeding populations of this species are migratory, dispersing widely after breeding before travelling southwards to the wintering grounds (del Hoyo et al. 1996). It breeds colonially in monospecific groups of 5-500 pairs (occasionally up to 1,000 pairs) or as solitary pairs amidst colonies of other species (del Hoyo et al. 1996), remaining gregarious outside of the breeding season (Snow and Perrins 1998). Habitat Breeding It breeds in a variety of locations with bare or sparsely vegetated islands, banks, flats, or spits of dry mud and sand (Higgins and Davies 1996) including barrier beaches (shoals), dunes, saltmarshes, saltpans (del Hoyo et al. 1996), freshwater lagoons (del Hoyo et al. 1996, Snow and Perrins 1998), estuaries, deltas (Snow and Perrins 1998), inland lakes, rivers, marshes (Snow and Perrins 1998) and swamps (Higgins and Davies 1996). During this season it may also feed on emerging insects over lakes, agricultural fields, grasslands and even over semi-desert regions (del Hoyo et al. 1996). Non-breeding On passage the species typically forages over saltpans, coastal lagoons, mudflats, marshes and wet fields (del Hoyo et al. 1996), overwintering on estuaries, saltpans (del Hoyo et al. 1996), lagoons (Snow and Perrins 1998) and saltmarshes (Higgins and Davies 1996) or in more inland sites such as large rivers, lakes, rice-fields (Snow and Perrins 1998), sewage ponds, reservoirs, saltpans and irrigation canals (Higgins and Davies 1996). Diet It is an opportunistic feeder and is largely insectivorous (del Hoyo et al. 1996) taking adult and larval terrestrial and aquatic insects (Richards 1990, del Hoyo et al. 1996) (such as Ephemeroptera, Odonata, Lepidoptera and Coleoptera) as well as spiders, earthworms, small reptiles, frogs, small fish (6-9 cm long), aquatic invertebrates and rarely voles and small birds (del Hoyo et al. 1996). Breeding site The nest is a scrape in dried mud, sand or gravel (Richards 1990) on beaches, dry mudflats, dykes, sea-wrack on the tideline or on floating vegetation (del Hoyo et al. 1996). Management information 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).

Threats
The species is threatened by the deterioration and loss of habitat, e.g. through wetland drainage, agricultural intensification, pesticide pollution, fluctuating water levels (del Hoyo et al. 1996), beach erosion and the development or modification of foraging sites (Molina and Erwin 2006). It also suffers from reduced reproductive successes as a result of human disturbance at breeding colonies (del Hoyo et al. 1996, Molina and Erwin 2006).

Related state of the world's birds case studies

References
Brazil, M. 2009. Birds of East Asia: eastern China, Taiwan, Korea, Japan, eastern Russia. Christopher Helm, London.

del Hoyo, J.; Elliott, A.; Sargatal, J. 1996. Handbook of the Birds of the World, vol. 3: Hoatzin to Auks. Lynx Edicions, Barcelona, Spain.

Delany, S.; Scott, D. 2006. Waterbird population estimates. Wetlands International, Wageningen, The Netherlands.

Fasola, M.; Canova, L. 1996. Conservation of gull and tern colony sites in north-eastern Italy, an internationally important bird area. Colonial Waterbirds 19: 59-67.

Higgins, P. J.; Davies, S. J. J. F. 1996. Handbook of Australian, New Zealand and Antarctic birds vol 3: snipe to pigeons. Oxford University Press, Oxford.

Molina, K. C.; Erwin, R. M. 2006. The Distribution and Conservation Status of the Gull-billed Tern (Gelochelidon nilotica) in North America. Waterbirds 29(3): 271-295.

Richards, A. 1990. Seabirds of the northern hemisphere. Dragon's World Ltd, Limpsfield, U.K.

Snow, D. W.; Perrins, C. M. 1998. The Birds of the Western Palearctic vol. 1: Non-Passerines. Oxford University Press, Oxford.

Further web sources of information
Detailed species account from Birds in Europe: population estimates trends and conservation status (BirdLife International 2004)

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

View photos and videos and hear sounds of this species from the Internet Bird Collection

Text account compilers
Ekstrom, J., Butchart, S., Malpas, L., Calvert, R.

Recommended citation
BirdLife International (2014) Species factsheet: Sterna nilotica. Downloaded from http://www.birdlife.org on 30/09/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 30/09/2014.

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.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Gull-billed tern (Sterna nilotica) 0

Key facts
Current IUCN Red List category Not Recognised
Family Laridae (Gulls, Terns, Skimmers)
Species name author Gmelin, 1789