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 Circus cyaneus

This taxon is Not Recognised as a species by BirdLife International.

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.
SACC. 2006. A classification of the bird species of South America. Available at: #

Taxonomic note
Circus cyaneus and C. hudsonius (del Hoyo and Collar 2014) were previously lumped as C. cyaneus following Sibley and Monroe (1990, 1993).

Behaviour In the northern part of its range, it is completely migratory, wintering in Europe (Scotland and further south), extreme North Africa, southern Asia, and from southern Canada south to Colombia in the New World. It leaves breeding grounds between August and November, returning between March and May (del Hoyo et al. 1994). Birds are generally solitary and hunt alone but gather at concentrations of food and roosts, where they typically number tens of individuals, and may form loose flocks on migration (del Hoyo et al. 1994, Snow and Perrins 1998, Ferguson-Lees and Christie 2001). Migration is usually on a broad front, with birds willing to cross wide expanses of water and thus not concentrating at narrow crossing points as do many raptors (del Hoyo et al. 1994, Snow and Perrins 1998).  Habitat It is generally a bird of open country, where there is some limited cover from vegetation (del Hoyo et al. 1994). Diet It generally feeds on small vertebrates, mostly mammals and birds (del Hoyo et al. 1994, Ferguson-Lees and Christie 2001). Breeding site The nest is made in dense vegetation on the ground (del Hoyo et al. 1994). Management information The species requires open habitat but some shrub cover is necessary (del Hoyo et al. 1994).

A marked decline in the North American population in the 1950s-1960s is thought to have resulted from excessive use of harmful organochlorine pesticides. Currently, the major threat to the species is habitat loss, from agricultural intensification, wetland draining and afforestation in parts of its range (del Hoyo et al. 1994, Ferguson-Lees and Christie 2001). Persecution is an important threat locally, notably on game preserves in Scotland (del Hoyo et al. 1994). It is also highly vulnerable to the impacts of potential wind energy developments (Strix 2012).

Brazil, M. 2009. Birds of East Asia: eastern China, Taiwan, Korea, Japan, eastern Russia. Christopher Helm, 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.; Christie, D. A. 2001. Raptors of the world. Christopher Helm, London.

Rich, T.D.; Beardmore, C.J.; Berlanga, H.; Blancher, P.J.; Bradstreet, M.S.W.; Butcher, G.S.; Demarest, D.W.; Dunn, E.H.; Hunter, W.C.; Inigo-Elias, E.E.; Martell, A.M.; Panjabi, A.O.; Pashley, D.N.; Rosenberg, K.V.; Rustay, C.M.; Wendt, J.S.; Will, T.C.

Snow, D. W.; Perrins, C. M. 1998. The Birds of the Western Palearctic vol. 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.

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., Khwaja, N.

Recommended citation
BirdLife International (2015) Species factsheet: Circus cyaneus. Downloaded from on 07/07/2015. Recommended citation for factsheets for more than one species: BirdLife International (2015) IUCN Red List for birds. Downloaded from on 07/07/2015.

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 - Northern harrier (Circus cyaneus) 0

Key facts
Current IUCN Red List category Not Recognised
Family Accipitridae (Hawks, Eagles)
Species name author (Linnaeus, 1766)