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Great Cormorant Phalacrocorax carbo

Justification
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 extremely 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: #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.
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.
Turbott, E. G. 1990. Checklist of the birds of New Zealand. Ornithological Society of New Zealand, Wellington.

Distribution and population
The Great Cormorant has an extremely large distribution, being found on every continent except South America and Antarctica. Colonies in North America are restricted to the north-east, although individuals do winter further south up to the tip of Florida (USA). Breeding colonies are also found in in western Greenland (to Denmark). In Europe, the it can be found along most of the Atlantic coast, as well as throught the Mediterranean and in large areas of Eastern Europe. In Africa, it can be found wintering of the northern coast as well as along the Nile, and breeding year-round on the north-west coast, in pockets of central-east Africa and in South Africa. Summer breeding occurs in patches through much of central Asia up to eastern China, year-round wintering occurs in India and southern China, and birds can be found wintering in south-east Asia. Finally, it can be found in most of Australia except central regions, and it also winters in New Zealand1.

Population justification
The global population is estimated to number c.1,400,000-2,900,000 individuals (Wetlands International 2006), while national population estimates include: >c.1,000 wintering individuals in China; c.100-10,000 breeding pairs and >c.1,000 wintering individuals in Korea; c.10,000-100,000 breeding pairs and >c.10,000 wintering individuals in Japan and possibly c.10,000-100,000 breeding pairs and c.1,000-10,000 individuals on migration in Russia (Brazil 2009).

Trend justification
The overall population trend is increasing, although some populations may be stable and others have unknown trends (Wetlands International 2006). This species has undergone a small or statistically insignificant increase over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007).

Ecology
Behaviour Throughout its range the species is sedentary or locally dispersive, with northerly populations also making strong migratory movements (del Hoyo et al. 1992). The timing of breeding varies geographically, occurring all year round (del Hoyo et al. 1992) or coinciding with the rains in the tropics (Johnsgard 1993) and peaking between April and June in the temperate regions of the Northern Hemisphere (del Hoyo et al. 1992). The species breeds in mixed-species colonies (del Hoyo et al. 1992) of 10-500 pairs (Nelson 2005) (occasionally up to 1,000 pairs) (Brown et al. 1982), the size of the colony depending upon the extent of nearby feeding areas (Nelson 2005). It is usually a solitary feeder (Brown et al. 1982) but may form large fishing flocks in some areas (del Hoyo et al. 1992). It also roosts communally at nesting sites or in major feeding areas and flies in flocks of varying sizes (Brown et al. 1982). Off the coasts of eastern Jutland and of Læsø, Denmark, flocks sizes of up to 890 individuals were observed (Petersen et al 2003). Feeding is exclusively diurnal. Habitat The species frequents both coastal and inland habitats (Brown et al. 1982, del Hoyo et al. 1992, Johnsgard 1993, Snow and Perrins 1998, Nelson 2005). In marine environments it occurs in sheltered coastal areas on estuaries (del Hoyo et al. 1992), saltpans, coastal lagoons (del Hoyo et al. 1992, Johnsgard 1993), mangrove swamps, deltas (Johnsgard 1993) and coastal bays (Brown et al. 1982), requiring rocky shores, cliffs and islets for nesting (del Hoyo et al. 1992) but generally avoiding deep water and rarely extending far offshore (Snow and Perrins 1998). It also inhabits fresh, brackish or saline inland wetlands (Nelson 2005) including lakes, reservoirs, wide rivers, flood waters (del Hoyo et al. 1992), deep marshes with open water, swamps and oxbow lakes (Johnsgard 1993), requiring trees, bushes, reedbeds or bare ground for nesting (del Hoyo et al. 1992) and avoiding overgrown, small, very shallow or very deep waters (Nelson 2005). Diet The species' diet consists predominantly of fish, including sculpins, Capelin, gadids (Gremillet et al 2004) and flatfish (Leopold et al 1998) as well as crustaceans, amphibians (del Hoyo et al. 1992), molluscs and nestling birds (Brown et al. 1982). At sea the species preys mostly on bottom-dwelling fish, occasionally also taking shoaling fish in deeper waters (del Hoyo et al. 1992). It is a generalist, having been shown to feed on at least 22 different fish species (Gremillet 1997). Breeding site The nest varies from a depression (Nelson 2005) to a platform of sticks, reeds and seaweed (del Hoyo et al. 1992). On the coast the species nests on inshore islands, cliffs, stacks, amongst boulders and occasionally on artificial structures (del Hoyo et al. 1992), also nesting inland on trees or bushes, in reedbeds or on bare ground (del Hoyo et al. 1992). The species usually nests in mixed-species colonies, often re-using sites and nests from year to year (del Hoyo et al. 1992). Foraging range The Great Cormorant has a largely neritic distribution. At sea, it rarely wanders far from the coast, preferring sheltered areas and estuaries where it normally feeds in shallow water. It preys mainly on benthic fish species. It is rarely observed to dive below 10 m (BirdLife International 2000, Petersen et al 2003, Gremillet et al 2004) although it has been recorded at up to 35 m (Gremillet et al 2004). Several studies have shown that this species is able to forage up to 20-25 km from its wintering roosts or breeding colonies. Most foraging trips are confined to within 10 km of the colony (Gremillet 1997, BirdLife International 2000, Petersen et al 2003), but trips up to a 35 km radius have been recorded (Gremillet 1997). Off the coasts of eastern Jutland and at Læsø, Denmark, 75% of recorded birds were seen within 3 km of the coast (Petersen et al 2003). Preferred habitats include granitic boulder, since this is the favoured habitat of labrids, the commonest prey in the diet (Gremillet 1997). The species is also likely to select sandy areas with a high abundance of flatfish or rocky substrates where gobies, wrasse, sea scorpions and small gadoids occur (BirdLife International 2000).

Threats
The species is often persecuted by the aquaculture industry and may be shot, drowned or poisoned in attempts to control numbers (Carss 1994). It may also suffer from disturbance from coastal wind farms (wind turbines) (Garthe and Huppop 2004), and is susceptible to avian influenza (Melville and Shortridge 2006) and Newcastle disease (Kuiken 1999) so may be threatened by future outbreaks of these viruses (Kuiken 1999, Melville and Shortridge 2006). Utilisation The species is hunted for recreation and is sold at commercial food markets in Iran (Balmaki and Barati 2006).

Conservation Actions Underway
It may be possible to alleviate conflicts between this species and fisheries by using such strategies as preventing birds from landing on fish ponds through disturbance, or creating unsuitable feeding conditions (Kirby et al. 1996).

Related state of the world's birds case studies

References
Balmaki, B.; Barati, A. 2006. Harvesting status of migratory waterfowl in northern Iran: a case study from Gilan Province. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 868-869. The Stationary Office, Edinburgh, 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).

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

Brown, L. H.; Urban, E. K.; Newman, K. 1982. The birds of Africa vol I. Academic Press, London.

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.

Garthe, S.; Hüppop, O. 2004. Scaling possible adverse effects of marine wind farms on seabirds: developing and applying a vulnerability index. Journal of Applied Ecology 41(4): 724-734.

Gremillet, D. 1997. Catch per unit effort, foraging efficiency, and parental investment in breeding great cormorants (Phalacrocorax carbo carbo). ICES Journal of Marine Science 54(4): 635-644.

Gremillet, D., Liu, H., Le Maho, Y. and Carss, D.N. 2003. Great cormorants and freshwater fish stocks: a pragmatic approach to an ecological issue. Cormoran 13(2 (supplement no.58)): 131-136.

Johnsgard, P. A. 1993. Cormorants, darters, and pelicans of the world. Smithsonian Institution Press, Washington.

Kirby, J. S.; Holmes, J. S.; Sellers, R. M. 1996. Cormorant Phalacrocorax carbo as fish predators: an appraisal of their conservation and management in Great Britain. Biological Conservation 75: 191-199.

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

Leopold, M.F., Van Damme, C.J.G. and Van der Weer, H.W. 1998. Diet of cormorants and the impact of cormorant predation on juvenile flatfish in the Dutch Wadden Sea. Journal of Sea Research 40(1-2): 93-107.

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.

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.

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)

Explore HBW Alive for further information on this species

Search for 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., Hatchett, J.

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

Recommended citation
BirdLife International (2014) Species factsheet: Phalacrocorax carbo. Downloaded from http://www.birdlife.org on 02/09/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 02/09/2014.

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 - Cormorant (Phalacrocorax carbo) 0

Key facts
Current IUCN Red List category Least Concern
Family Phalacrocoracidae (Cormorants)
Species name author (Linnaeus, 1758)
Population size mature individuals
Population trend Increasing
Distribution size (breeding/resident) 24,600,000 km2
Country endemic? No
Links to further information
- Additional Information on this species
- Projected distributions under climate change