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 10 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 10 years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
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#.
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.
Behaviour It is mainly migratory, with populations in Western Europe, North Africa and at the south of its range in Asia being generally resident (del Hoyo et al. 1994, Ferguson-Lees and Christie 2001). Migrant birds leave their breeding grounds in September and October, wintering from France south as far as sub-Saharan Africa, and east as far as the Middle East (del Hoyo et al. 1994). They begin their return journey in February and March, arriving in March and April (del Hoyo et al. 1994, Snow and Perrins 1998, Ferguson-Lees and Christie 2001). Migration is generally on a broad front, although there is some concentration at a few sites (Brown et al. 1982). Hundreds of birds occasionally gather at roosting sites, sometimes with other harriers such as C. pygargus, but otherwise they are usually solitary, associating only temporarily at especially rich feeding sites (del Hoyo et al. 1994, Snow and Perrins 1998, Ferguson-Lees and Christie 2001). They have a slightly greater tendency to be gregarious while on migration but the above still generally applies. Birds fly c. 10-30 m above the ground (Brown et al. 1982). Habitat The species inhabits extensive areas of dense marsh vegetation, in fresh or brackish water, generally in lowlands but up to 2,000 m in Asia and 3,000 m on its wintering grounds in Cameroon (del Hoyo et al. 1994). Diet It is a generalist predator taking a variety of prey types, with small birds generally preferred but mammals such as voles, rabbits and rats being more important in parts of its range (del Hoyo et al. 1994). Breeding site The nest is a pile of reeds built in dense marsh vegetation (del Hoyo et al. 1994). Management information The species requires extensive wetland in its breeding range (del Hoyo et al. 1994).
Major threats include wetland desiccation and drainage; persecution by shooting; pollution, especially from excessive pesticide use in and around wetlands (although widespread bans have reduced this threat somewhat), and poisoning by heavy metals, notably the consumption of lead-shot through feeding on contaminated waterbirds (del Hoyo et al. 1994, Ferguson-Lees and Christie 2001, Orta et al. 2014). The historical threat of hunting in southern Europe has mostly subsided, but illegal shooting is still rife locally, notably on Malta (Ferguson-Lees and Christie 2001). The species is also highly vulnerable to the effects of potential wind energy development (Strix 2012). In its West African range, the species is vulnerable to habitat degradation through wood harvesting and overgrazing as well as exposure to pesticides (Thiollay 2007).
BirdLife International. 2004. Birds in Europe: population estimates, trends and conservation status. BirdLife International, Cambridge, U.K.
BirdLife International. 2015. European Red List of Birds. Office for Official Publications of the European Communities, Luxembourg.
Brown, L.H., Urban, E.K. and Newman, K. 1982. The Birds of Africa, Volume I. Academic Press, London.
del Hoyo, J.; Elliott, A.; Sargatal, J. 1994. Handbook of the Birds of the World, vol. 2: New World Vultures to Guineafowl. Lynx Edicions, Barcelona, Spain.
Ferguson-Lees, J. and Christie, D.A. 2001. Raptors of the world. Christopher Helm, London.
IUCN. 2015. The IUCN Red List of Threatened Species. Version 2015-4. Available at: www.iucnredlist.org. (Accessed: 19 November 2015).
Orta, J., Boesman, P., Marks, J.S. and Garcia, E.F.J. 2014. Western Marsh-harrier (Circus aeruginosus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. and de Juana, E. (eds), Handbook of the Birds of the World Alive, Lynx Edicions, Barcelona.
Snow, D.W. and Perrins, C.M. 1998. The Birds of the Western Palearctic, Volume 1: Non-Passerines. Oxford University Press, Oxford.
STRIX. 2012. Developing and testing the methodology for assessing and mapping the sensitivity of migratory birds to wind energy development. BirdLife International, Cambridge.
Thiollay, J.-M. 2007. Raptor population decline in West Africa. Ostrich 78(2): 405-413.
Further web sources of information
Detailed species account from Birds in Europe: population estimates trends and conservation status (BirdLife International 2004)
Text account compilers
Butchart, S., Ekstrom, J., Harding, M., Khwaja, N. & Ashpole, J
IUCN Red List evaluators
BirdLife International (2016) Species factsheet: Circus aeruginosus. Downloaded from http://www.birdlife.org on 29/09/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 29/09/2016.
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
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Additional resources for this species
|Current IUCN Red List category||Least Concern|
|Family||Accipitridae (Hawks, Eagles)|
|Species name author||(Linnaeus, 1758)|
|Population size||500000-999999 mature individuals|
|Distribution size (breeding/resident)||13,500,000 km2|
|Links to further information|
- Additional Information on this species|
- 2015 European Red List assessment