Hydroprogne caspia 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Laridae

Scientific Name: Hydroprogne caspia (Pallas, 1770)
Regional Assessments:
Common Name(s):
English Caspian Tern
French Sterne caspienne
Hydroprogne caspia — AOU checklist (1998 + supplements)
Hydroprogne caspia — Stotz et al. (1996)
Hydroprogne caspia — Christidis and Boles (2008)
Sterna caspia Pallas, 1770
Taxonomic Source(s): Cramp, S. and Simmons, K.E.L. (eds). 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
Taxonomic Notes: Hydroprogne caspia (del Hoyo and Collar 2014) was previously placed in the genus Sterna.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2017
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Dowsett, R.J.
Facilitator/Compiler(s): Butchart, S., Calvert, R., Ekstrom, J., Malpas, L., Ashpole, J
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 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). 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:

Geographic Range [top]

Range Description:This species has a cosmopolitan but scattered distribution. Their breeding habitat is large lakes and ocean coasts in North America (including the Great Lakes), and locally in Europe (mainly around the Baltic Sea and Black Sea), Asia, Africa, and Australasia (Australia and New Zealand). North American birds migrate to southern coasts, the West Indies and northernmost South America. European and Asian birds winter in the Old World tropics. African and Australasian birds are resident or disperse over short distances (del Hoyo et al. 1996).
Countries occurrence:
Afghanistan; Albania; Algeria; Angola; Aruba; Australia; Austria; Azerbaijan; Bahamas; Bahrain; Bangladesh; Barbados; Belarus; Belize; Benin; Botswana; Brunei Darussalam; Bulgaria; Burkina Faso; Cambodia; Cameroon; Canada; Cayman Islands; Central African Republic; Chad; China; Colombia; Comoros; Congo; Costa Rica; Côte d'Ivoire; Cuba; Cyprus; Czech Republic; Djibouti; Dominican Republic; Egypt; El Salvador; Equatorial Guinea; Eritrea; Estonia; Ethiopia; Finland; France; French Guiana; Gabon; Gambia; Germany; Ghana; Greece; Guatemala; Guinea; Guinea-Bissau; Haiti; Honduras; Hong Kong; Hungary; India; Indonesia; Iran, Islamic Republic of; Iraq; Israel; Italy; Jamaica; Japan; Jordan; Kazakhstan; Kenya; Kuwait; Lao People's Democratic Republic; Latvia; Liberia; Libya; Lithuania; Macedonia, the former Yugoslav Republic of; Madagascar; Malaysia; Maldives; Mali; Malta; Mauritania; Mayotte; Mexico; Moldova; Mongolia; Morocco; Mozambique; Myanmar; Namibia; Nepal; Netherlands; New Zealand; Nicaragua; Niger; Nigeria; Oman; Pakistan; Palestinian Territory, Occupied; Panama; Philippines; Poland; Portugal; Puerto Rico; Qatar; Romania; Russian Federation (Central Asian Russia, Eastern Asian Russia, European Russia); Saint Pierre and Miquelon; Saudi Arabia; Senegal; Seychelles; Sierra Leone; Singapore; Slovakia; Somalia; South Africa; South Sudan; Spain; Sri Lanka; Sudan; Sweden; Switzerland; Syrian Arab Republic; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Timor-Leste; Togo; Trinidad and Tobago; Tunisia; Turkey; Turkmenistan; Turks and Caicos Islands; Uganda; Ukraine; United Arab Emirates; United States; Uzbekistan; Venezuela, Bolivarian Republic of; Viet Nam; Western Sahara; Yemen; Zambia; Zimbabwe
Regionally extinct:
Anguilla; Antigua and Barbuda; Belgium; Bermuda; Burundi; Congo, The Democratic Republic of the; Croatia; Dominica; Ecuador; Faroe Islands; Gibraltar; Guadeloupe; Ireland; Kyrgyzstan; Luxembourg; Martinique; Montenegro; Norway; Rwanda; Saint Kitts and Nevis; Saint Lucia; Serbia; Slovenia; Swaziland; United Kingdom; Virgin Islands, U.S.
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:187000000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The global population is estimated to number c.250,000-470,000 individuals (Wetlands International 2015). The European population is estimated at 11,800-14,800 pairs, which equates to 23,600-29,600 mature individuals (BirdLife International 2015). National population estimates include: c.50-1,000 individuals on migration and c.50-1,000 wintering individuals in China; c.50-1,000 individuals on migration and c.50-1,000 wintering individuals in Taiwan; < c.50 individuals on migration and < c.50 wintering individuals in Japan and c.100-10,000 breeding pairs and c.50-1,000 individuals on migration in Russia (Brazil 2009).

Trend Justification:  The overall population trend is increasing, although some populations are decreasing, stable, or have unknown trends (Wetlands International 2006). This species has undergone a large and statistically significant increase over the last 40 years in North America (266% increase over 40 years, equating to a 38.3% increase per decade; data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007). The European population trend is estimated to be increasing (BirdLife International 2015).
Current Population Trend:Increasing
Additional data:
Continuing decline of mature individuals:Unknown
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:Behaviour Although populations breeding near the equator are largely sedentary (Richards 1990), northern populations are strongly migratory and disperse after breeding before migrating southwards (del Hoyo et al. 1996). The species breeds between April and June (northern Hemisphere) or between September and December (southern Hemisphere) (del Hoyo et al. 1996) in large dense monospecific colonies or as single pairs or small groups (2-3 pairs) amidst large colonies of other species (Flint et al. 1984, del Hoyo et al. 1996, Snow and Perrins 1998). It is not a highly gregarious species outside of the breeding season (Snow and Perrins 1998) but may aggregate into flocks on passage (Urban et al. 1986), and during the winter it may feed in loose congregations (del Hoyo et al. 1996) in rich fishing areas or at nightly roost sites (Snow and Perrins 1998). Habitat The breeding, passage and wintering habitats of this species are similar, although during the winter it is largely confined to the coast (Shuford and Craig 2002). It frequents sheltered sea coasts (del Hoyo et al. 1996, Snow and Perrins 1998), estuaries (Richards 1990, Higgins and Davies 1996, del Hoyo et al. 1996), inlets, bays, harbours (Higgins and Davies 1996), coastal lagoons (Higgins and Davies 1996, Snow and Perrins 1998), saltmarshes (del Hoyo et al. 1996) and saltpans (Martin and Randall 1987, Higgins and Davies 1996), also occurring inland on fresh or saline wetlands including large lakes, inland seas (Richards 1990, del Hoyo et al. 1996), large rivers (Flint et al. 1984, Higgins and Davies 1996), creeks (Higgins and Davies 1996), floodlands (Snow and Perrins 1998), reservoirs (Richards 1990, Higgins and Davies 1996, del Hoyo et al. 1996) and sewage ponds (Higgins and Davies 1996). When breeding the species shows a preference for nesting on sandy, shell-strewn or shingle beaches (Flint et al. 1984, Snow and Perrins 1998), sand-dunes, flat rock-surfaces (Snow and Perrins 1998), sheltered reefs (Higgins and Davies 1996) or islands (Flint et al. 1984, del Hoyo et al. 1996, Snow and Perrins 1998) with sparse vegetation and flat or gently sloping margins surrounded by clear, shallow, undisturbed waters (Snow and Perrins 1998). It also forms winter roosts on sandbars, mudflats and banks of shell (del Hoyo et al. 1996). Diet Its diet consists predominantly of fish 5-25 cm in length (Shuford and Craig 2002) as well as the eggs and young of other birds, carrion (del Hoyo et al. 1996), aquatic invertebrates (Flint et al. 1984) (e.g. crayfish) (Shuford and Craig 2002), flying insects (Urban et al. 1986, Shuford and Craig 2002) and earthworms (Shuford and Craig 2002). Breeding site The nest is a shallow depression in the sand, gravel, shells, sparse vegetation (del Hoyo et al. 1996) or dried mud (Richards 1990) of ridges, beaches (Flint et al. 1984, Higgins and Davies 1996, Snow and Perrins 1998), dunes (Snow and Perrins 1998), flat rocky or stony islets, banks (Higgins and Davies 1996), islands or reefs in seas, lakes and large rivers (Flint et al. 1984), dredge spoil piles and islands in reservoirs (Higgins and Davies 1996). The species nests in large colonies or as single pairs or small groups amidst colonies of other species, neighbouring nests placed between 0.7 and 4 m part (del Hoyo et al. 1996). The species may forage up to 60 km from the site of the breeding colony (del Hoyo et al. 1996). Management information Management for this species should include a number of measures such as habitat and vegetation management, the use of artificial nest substrates, predator management (e.g. control of gull populations) and the minimisation of disturbance (Shuford and Craig 2002). Habitat and vegetation management may include the creation of artificial islands with calm water on their leeward side to allow the growth of submerged vegetation and fish spawning habitats, or alternatively the creation of floating artificial nesting-rafts (e.g. barges covered with sand) (Shuford and Craig 2002).
Systems:Terrestrial; Freshwater; Marine
Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):12.2
Movement patterns:Full Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s): The species is currently threatened by the loss and deterioration of breeding habitat through accelerated vegetation succession (possibly through the introduction of exotic plant species) (Shuford and Craig 2002) and may be threatened in the future by habitat loss through inundation as a result of sea-level rise (Shuford and Craig 2002). The species is vulnerable to human disturbance at nesting colonies (Blokpoel and Scharf 1991) especially during the early-courtship and incubation periods (Shuford and Craig 2002), and exposure to bioaccumulated contaminants (e.g. organochlorines or methylmercury) in fish could be lowering the species's reproductive success (del Hoyo et al. 1996). Newcastle disease (Shuford and Craig 2002, Kuiken et al. 2006) and avian botulism may also threaten concentrated local populations (although these diseases are unlikely to threaten the global population as a whole) (Shuford and Craig 2002). It is vulnerable to oil spills and marine pollution. It is susceptible to being caught as bycatch in fishing gears.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
The following information refers to the species's European range only: The species is listed on Appendix II of the Convention on Migratory Species. It is covered by the African Eurasian Waterbird Agreement. It is listed on Appendix II of the Bern Convention. In the EU it is listed on Annex I of the Birds Directive. There are 66 Important Bird Areas identified for this species within Europe. Within the EU there are 320 Special Protection Areas which include this species. 

Conservation Actions Proposed
The following information refers to the species's European range only: Management of existing protected areas for site based threats. On board observer programmes to monitor bycatch events on fishing vessels and implement mitigation measures where appropriate.

Amended [top]

Amended reason: Edited the origin/seasonality of occurrence for Benin. Added a Contributor.

Citation: BirdLife International. 2017. Hydroprogne caspia (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2017: e.T22694524A111757252. . Downloaded on 27 May 2018.
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