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European Shag Phalacrocorax aristotelis
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This species has a very 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). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to 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.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: # _the_WP15.xls#.
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.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

Distribution and population
The European Shag can be found along the entire Atlantic coast of Europe as far north as Finland and including Iceland, as far south as the coast of Morocco, and ranges in the entire Mediterranean nesting on parts of the coastline of most European (e.g. Italy, Turkey) and north African countries (e.g. Algeria, Libya), as well as parts of the Black Sea coast (e.g. Ukraine) (del Hoyo et al. 1992).

Trend justification
The overall trend is decreasing, although some populations may be stable (Wetlands International 2006).

Behaviour The European Shag is a coastal species that shows high nesting site fidelity. It feeds exclusively diurnally, and one bird is always present with the clutch or brood during the breeding season. The species breeds in colonies (del Hoyo et al. 1992) that can hold more than a thousand well-spaced pairs (Snow and Perrins 1998, Nelson 2005). It is largely sedentary (del Hoyo et al. 1992), although immatures may undergo post-breeding dispersive movements over short distances (del Hoyo et al. 1992). Some birds undergo short-distance migrations during winter. Individuals often forage alone when away from nesting colonies and in winter (del Hoyo et al. 1992, Snow and Perrins 1998), but may follow dense shoals of fish in flocks of several hundred individuals (Nelson 2005). Habitat It occupies marine habitats but does not usually occur far from land (del Hoyo et al. 1992). It shows a strong preference for rocky coasts and islands (del Hoyo et al. 1992) with adjacent deep, clear water (Nelson 2005), and forages over sandy and rocky seabeds (del Hoyo et al. 1992). It also prefers sheltered fishing grounds such as bays and channels, although it generally avoids estuaries, shallow or muddy inlets and fresh or brackish waters (Wanless and Harris 1997). Diet The species feeds on a wide range of benthic, demersal and schooling, pelagic fish. Sandeels (Ammodytidae) are the dominant prey of birds in British and some Spanish populations (Wanless et al 1997, Velando and Friere 1999, BirdLife International 2000, Velando et al. 2005), and are consistently present in the species' diet in most other locations studied. These are usually caught at, or near, the sea bed (Wanless et al 1997). Other prey species include fish of the families Gadidae, Clupeidae, Cottidae, Labridae, and Trisopterus spp. (del Hoyo et al. 1992), although birds also take small numbers of polychaetes, cephalopods, other molluscs and small benthic crustaceans (Wanless and Harris 1997). Adults provision their chicks with sandeels, but consume a broader variety of prey for themselves (BirdLife International 2000). The Mediterranean subspecies feeds mainly on coastal fishes, caught from the bottom or mid water over rocky or sandy seabeds, but economically important fish seem to form a very small part of the diet (Aguilar and Fernandez 1999). Breeding site The nest is constructed of marine vegetation and flotsam (del Hoyo et al. 1992, Nelson 2005), from just above the high water level to over 100 m high (Snow and Perrins 1998) on ledges, in crevices or in caves on sea cliffs, rocks and stacks, and at the base of sea cliffs amongst boulders (del Hoyo et al. 1992). Foraging range At Islas Cíes, Spain, birds foraged within 20 km of the colony all year round (Velando et al. 2005). During the breeding season, the foraging range was typically within 4 km of the colony, and birds foraged in groups of 300-1000 individuals (Velando et al. 2005). Foraging areas tend to coincide with areas of sandy benthic sediment (Wanless et al 1991, BirdLife International 2000, Velando et al. 2005), and occur where depth is less than 80 m (Wanless et al 1991, Velando and Friere 1999). At the Isle of May, Scotland, over 90% of foraging occurred within 13 km of the colony, and the maximum distance recorded was 17 km (Wanless et al 1991). Foraging individuals visited more than one area during a trip, often feeding at sites several kilometres apart (Wanless et al 1991). Birds were often found feeding in areas of strong tidal flow (Wanless et al 1991). The available data on European Shag feeding habitat suggest that, within the inshore zone as a whole, the species is fairly plastic in its habitat requirements. In some areas, the birds' foraging range is considerably less than 20 km; the small number of birds breeding at Hirta, Scotland, all appeared to forage within a 2 km radius (BirdLife International 2000). Similarly, birds were only present within 3 km of North Rona, Scotland (BirdLife International 2000).

The species is persecuted (e.g. shot, intentionally drowned or poisoned) at commercial fisheries and fish farms as it is perceived to be a threat to fish stocks (Carss 1994, Wanless and Harris 1997). It also suffers predation at nesting colonies by introduced American mink Neovison vison (Wanless and Harris 1997), is vulnerable to coastal oil pollution (Wanless and Harris 1997, Velando et al. 2005), locally suffers from accidental entanglement and subsequent drowning in gill-nets (fishing nets) (Wanless and Harris 1997, Velando and Freire 2002), and is susceptible to the Newcastle disease so may be threatened by future outbreaks of the virus (Kuiken 1999). Utilisation Eggs, chicks and adults are taken from colonies for food (Wanless and Harris 1997).

Related state of the world's birds case studies

Aguilar, J.S. and Fernandez, G. 1999. Species action plan for the Mediterranean shag Phalacrocorax aristotelisdesmarestii in Europe. BirdLife International, Cambridge, UK.

BirdLife International. 2000. The Development of Boundary Selection Criteria for the Extension of Breeding Seabird Special Protection Areas into the Marine Environment. OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic. Vlissingen (Flushing).

Carss, D. N. 1994. Killing of piscivorous birds at Scottish fin fish farms, 1984-1987. Biological Conservation 68: 181-188.

del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.

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

Fredriksen, M.; Harris, M. P.; Daunt, F.; Rothery, P.; Wanless, S. 2004. Scale-dependent climate signals drive breeding phenology of three seabird species. Global Change Biology 10: 1214-1221.

Kuiken, T. 1999. Review of Newcastle disease in Cormorants. Waterbirds 22(3): 333-347.

Nelson, J. B. 2005. Pelicans, cormorants and their relatives. Pelecanidae, Sulidae, Phalacrocoracidae, Anhingidae, Fregatidae, Phaethontidae. Oxford University Press, Oxford, U.K.

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

Velando, A.; Freire, J. 2002. Population modelling of European shags (Phalacrocorax aristotelis) at their southern limit: Conservation implications. Biological Conservation 107(1): 59-69.

Velando, A.; Munilla, I.; Leyenda, P. M. 2005. Short-term indirect effects of the 'Prestige' oil spill on European shags: changes in availability of prey. Marine Ecology Progress Series 302: 263-274.

Wanless, S., Harris, M.P. and Morris, J.A. 1991. Foraging range and feeding locations of shags Phalacrocorax aristotelis during chick rearing. Ibis 133: 30-36.

Wanless, S.; Harris, M. P. 1997. Phalacrocorax aristotelis Shag. Birds of the Western Palearctic Update 1(1): 3-13.

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)

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

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2016) Species factsheet: Phalacrocorax aristotelis. Downloaded from on 23/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 23/10/2016.

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 - Shag (Phalacrocorax aristotelis) 0

Key facts
Current IUCN Red List category Least Concern
Family Phalacrocoracidae (Cormorants)
Species name author (Linnaeus, 1761)
Population size mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 234,000 km2
Country endemic? No
Links to further information
- Additional Information on this species
- 2015 European Red List assessment