Chlidonias leucopterus -- (Temminck, 1815)ANIMALIA -- CHORDATA -- AVES -- CHARADRIIFORMES -- LARIDAECommon names: White-winged Tern; Guifette leucoptère; White-winged Black Tern

European Red List AssessmentEuropean Red List Status

LC -- Least Concern, (IUCN version 3.1)

Assessment InformationYear published: 2015Date assessed: 2015-03-31Assessor(s): BirdLife InternationalReviewer(s): Symes, A.Compiler(s): Ashpole, J., Burfield, I., Ieronymidou, C., Pople, R., Tarzia, M., Wheatley, H. & Wright, L.Assessment RationaleEuropean regional assessment: Least Concern (LC)EU27 regional assessment: Least Concern (LC)

In Europe this species has an extremely 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 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). For these reasons the species is evaluated as Least Concern in Europe.

Within the EU27 this species 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 in the EU27.

OccurrenceCountries/Territories of OccurrenceNative:Albania; Armenia; Austria; Azerbaijan; Belarus; Bosnia and Herzegovina; Bulgaria; Croatia; Cyprus; Czech Republic; Denmark; Estonia; France; Georgia; Germany; Greece; Hungary; Italy; Latvia; Lithuania; Macedonia, the former Yugoslav Republic of; Malta; Moldova; Montenegro; Netherlands; Poland; Romania; Russian Federation; Serbia; Slovakia; Slovenia; Spain; Switzerland; Turkey; UkraineVagrant:Belgium; Faroe Islands (to DK); Finland; Iceland; Ireland, Rep. of; Luxembourg; Norway; Portugal; Sweden; United Kingdom; Gibraltar (to UK)

PopulationThe European population is estimated at 66,600-173,000 pairs, which equates to 133,000-347,000 mature individuals. The population in the EU27 is estimated at 550-18,200 pairs, which equates to 1,100-36,400 mature individuals. For details of national estimates, see Supplementary PDF.

TrendIn Europe the population size is estimated to be fluctuating. In the EU27 the population size is estimated to be increasing. For details of national estimates, see Supplementary PDF.

Habitats and EcologyThe species breeds inland on freshwater lakes (Snow and Perrins 1998, Gochfeld et al. 2013), swampy standing water, rivers (Snow and Perrins 1998) and shallow naturally flooded grassland (Richards 1990, Snow and Perrins 1998) with areas of open water bordered by stands of reeds, sedge and other aquatic vegetation (Snow and Perrins 1998). It generally avoids fish-ponds, rice-fields and ornamental waters (Richards 1990) but may feed over wet fields, dry farmland and steppe grassland. It breeds from April to

August in small colonies of between 3 and 100 pairs (mostly 20–40 pairs) that may contain other species.

The nest is a shallow cup in a mound of aquatic vegetation usually placed over water 30–120 cm deep on floating mats of vegetation, or on dry shores or resting on the bottom in shallow water. Clutches are two or three eggs. The species nests in single- or mixed-species colonies, neighbouring nests usually widely spaced (10–30 m apart) but may be as close as 2.5 m. Its diet consists predominantly of aquatic insects (especially Diptera, Odonata and Coleoptera) as well as adult and larval terrestrial insects, small fish and tadpoles. This species is strongly migratory (Gochfeld et al. 2013). Throughout the year the species feeds in flocks (Snow and Perrins 1998) and migrates and overwinters in large flocks (Gochfeld et al. 2013) of up to tens of thousands of individuals (Snow and Perrins 1998).Habitats & Altitude

Habitat (level 1 - level 2) Importance OccurrenceArtificial/Aquatic - Seasonally Flooded Agricultural Land suitable breedingMarine Intertidal - Rocky Shoreline suitable passageMarine Intertidal - Tidepools suitable passageWetlands (inland) - Bogs, Marshes, Swamps, Fens, Peatlands major breedingWetlands (inland) - Permanent Freshwater Lakes (over ha) suitable breedingAltitude max. 2000 m Occasional altitudinal limits

ThreatsThe main threats to this species are habitat destruction and water regulation in wetlands. In the west of its range the reclamation of wetlands is causing declines and in Russia and the Ukraine dry breeding seasons and an increasing number of drainage schemes pose a threat (Hagemeijer and Blair 1997). In Poland it is threatened by recreational activities causing disturbance (Górski 2004). It is also susceptible to avian influenza so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006).Threats & Impacts

Threat (level 1) Threat (level 2) Impact and StressesHuman intrusions & disturbance

Recreational activities

Timing Scope Severity ImpactOngoing Majority (50-90%) Unknown Unknown

StressesSpecies disturbance

Invasive and other problematic species, genes & diseases

American Mink (Neovison vison)

Timing Scope Severity ImpactOngoing Majority (50-90%) Slow, Significant

DeclinesMedium Impact

StressesSpecies mortality

Invasive and other problematic species, genes & diseases

Avian Influenza Virus (H subtype)

Timing Scope Severity ImpactPast, Likely to Return

Whole (>90%) Rapid Declines Past Impact

StressesSpecies mortality

Invasive and other problematic species, genes & diseases

Domestic Cat (Felis catus)

Timing Scope Severity ImpactOngoing Majority (50-90%) Slow, Significant

DeclinesMedium Impact

StressesSpecies mortality

Invasive and other problematic species, genes & diseases

Unspecified rats (Rattus spp.)

Timing Scope Severity ImpactOngoing Majority (50-90%) Slow, Significant

DeclinesMedium Impact

StressesSpecies mortality

Natural system modifications

Abstraction of surface water (unknown use)

Timing Scope Severity ImpactOngoing Minority (<50%) Slow, Significant

DeclinesLow Impact

StressesEcosystem degradation

Conservation

Conservation Actions UnderwayBern Convention Appendix II. There are currently no known conservation measures for this species.

Conservation Actions ProposedThis species would likely benefit from the protection and conservation of its preferred wetland habitats. Restrictions on access and exclusion zones would help prevent disturbance at key sites.

BibliographyGochfeld, M., Burger, J. & Christie, D.A. (2013). White-winged Tern (Chlidonias leucopterus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2013). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/54046 on 1 April 2015).Górski A. 2004. Chlidonias leucopterus (Temm., 1815) – rybitwa białoskrzydła. W: Gromadzki M. (red.) Ptaki (część II). Poradniki ochrony siedlisk i gatunków Natura 2000 – podręcznik metodyczny. Ministerstwo Środowiska, Warszawa. T. 8, s. 208–211.Melville, D. S.; Shortridge, K. F. 2006. Migratory waterbirds and avian influenza in the East Asian-Australasian Flyway with particular reference to the 2003-2004 H5N1 outbreak. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 432-438. The Stationary Office, Edinburgh, UK.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)