Gelochelidon nilotica -- (Gmelin, 1789) ANIMALIA -- CHORDATA -- AVES -- -- Common names: Common -billed Tern; European Red List Assessment European Red List Status LC -- Least Concern, (IUCN version 3.1) Assessment Information Year published: 2015 Date assessed: 2015-03-31 Assessor(s): BirdLife International Reviewer(s): Symes, A. Compiler(s): Ashpole, J., Burfield, I., Ieronymidou, C., Pople, R., Wheatley, H. & Wright, L. Assessment Rationale European regional assessment: Least Concern (LC) EU27 regional assessment: Least Concern (LC)

At both European and EU27 scales this has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence 10% in ten years or three generations, or with a specified population structure). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (30% decline over ten years or three generations).

For these reasons the species is evaluated as Least Concern within both and the EU27. Occurrence Countries/Territories of Occurrence Native: Armenia; Azerbaijan; Bulgaria; Denmark; France; Germany; Greece; Italy; Portugal; Romania; Russian Federation; Spain; Turkey; Ukraine Vagrant: Belgium; Bosnia and Herzegovina; Croatia; Finland; Hungary; Ireland, Rep. of; Luxembourg; Montenegro; Norway; Poland; Serbia; Slovakia; Slovenia; Sweden; United Kingdom Population The European population is estimated at 16,600-21,200 pairs, which equates to 33,200-42,400 mature individuals. The population in the EU27 is estimated at 8,000-9,200 pairs, which equates to 16,100-18,300 mature individuals. For details of national estimates, see Supplementary PDF. Trend In Europe and the EU27 the population size is estimated to be increasing. For details of national estimates, see Supplementary PDF. Habitats and Ecology 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, freshwater lagoons (Gochfield and Burger 1996), estuaries, deltas, inland lakes, rivers and marshes (Snow and Perrins 1998). During this season it may also feed on emerging insects over lakes, agricultural fields, grasslands and even over semi-desert regions (Gochfield and Burger 1996). On passage the species typically forages over saltpans, coastal lagoons, mudflats, marshes and wet fields, overwintering on estuaries, saltpans (Gochfield and Burger 1996), lagoons (Snow and Perrins 1998) and saltmarshes (Higgins and Davies 1996) or in more inland sites such as large rivers, lakes (Snow and Perrins 1998), sewage ponds, reservoirs, saltpans and irrigation canals (Higgins and Davies 1996). The species is loosely colonial; usually 5–50 pairs found together. It will often nest in the colonies of other terns or ridibundus. Egg-laying occurs in May and June. The nest is a scrape in dry mud, sand or gravel (Richards 1990) on beaches, dry mudflats, dykes, sea- wrack on the tideline or on floating vegetation (Gochfield and Burger 1996). It is an opportunistic feeder and is largely insectivorous taking adult and larval terrestrial and aquatic insects (Richards 1990, Gochfield and Burger 1996) as well as spiders, earthworms, small reptiles, frogs, small fish (6–9 cm long), aquatic invertebrates and rarely voles and small . Northern breeding populations of this species are migratory and European birds disperse in all directions after breeding, then migrate across to Spain, Italy and northern Africa to western Africa, the Rift Valley and coastal eastern Africa; others travel east to India, and occasionally Indonesia (Gochfield and Burger 1996). Habitats & Altitude Habitat (level 1 - level 2) Importance Occurrence Artificial/Aquatic - Irrigated Land (includes irrigation channels) suitable breeding Artificial/Aquatic - Water Storage Areas (over ha) major breeding Marine Coastal/Supratidal - Coastal Brackish/Saline Lagoons/Marine Lakes suitable breeding Marine Coastal/Supratidal - Coastal Freshwater Lakes suitable breeding Marine Coastal/Supratidal - Coastal Sand Dunes major breeding Marine Intertidal - Sandy Shoreline and/or Beaches, Sand Bars, Spits, Etc major breeding Marine Neritic - Estuaries suitable breeding Wetlands (inland) - Permanent Freshwater Lakes (over ha) suitable breeding Wetlands (inland) - Permanent Rivers/Streams/Creeks (includes waterfalls) suitable breeding Wetlands (inland) - Seasonal/Intermittent Freshwater Lakes (over ha) suitable breeding Altitude max. 100 m Occasional altitudinal limits Threats The species is threatened by the deterioration and loss of habitat, e.g. through wetland drainage, agricultural intensification, pesticide pollution, fluctuating water levels (Gochfeld and Burger 1996), beach erosion and the development or modification of foraging sites (Molina and Erwin 2006). It also suffers from reduced reproductive success as a result of human disturbance at breeding colonies (Gochfeld and Burger 1996, Molina and Erwin 2006). Threats & Impacts Threat (level 1) Threat (level 2) Impact and Stresses Agriculture & Agro-industry Timing Scope Severity Impact aquaculture farming Ongoing Whole (>90%) Slow, Significant Medium Impact Declines Stresses Ecosystem conversion; Ecosystem degradation Biological resource Hunting & trapping Timing Scope Severity Impact use terrestrial Ongoing Majority (50-90%) Negligible declines Low Impact (intentional use - species is the target) Stresses Species mortality Human intrusions & Work & other Timing Scope Severity Impact disturbance activities Ongoing Majority (50-90%) Negligible declines Low Impact Stresses Reduced reproductive success Natural system Abstraction of Timing Scope Severity Impact modifications surface water Ongoing Whole (>90%) Negligible declines Medium Impact (unknown use) Stresses Ecosystem conversion; Ecosystem degradation Pollution Herbicides and Timing Scope Severity Impact pesticides Past, Unlikely to Majority (50-90%) Slow, Significant Past Impact Return Declines Stresses Ecosystem conversion; Ecosystem degradation Conservation Conservation Actions Underway CMS Appendix II. EU Birds Directive Annex I. Bern Convention Appendix II. There are currently no known conservation measures for this species. Conservation Actions Proposed Identify important breeding areas for the species and ensure site protection from disturbance, development and modification. Develop and implement suitable site management plans. Studies should be conducted to investigate the species's population ecology and potential threats and impacts, in order to inform conservation measures. Bibliography Gochfeld, M. & Burger, J. (1996). Common Gull-billed Tern ( nilotica). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2014). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/54012 on 22 January 2015). Molina, K. C.; Erwin, R. M. 2006. The Distribution and Conservation Status of the Gull-billed Tern ( Gelochelidon nilotica) in . 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. Map (see overleaf)