Includes: Hen Harrier, Marsh Hawk
- Circus cyaneus
Identification
A medium-sized raptor, 45-55 cm (17¾-21¾ in) long and 97-122 cm wingspan; males smaller (350 g), females larger (530 g).
Male
- Grey head and upper parts
- Black primaries
- White rump. Plain grey in Hen Harrier C. c. cyaneus, mottled darker in Northern Harrier C. c. hudsonius.
Female: Quite a bit larger than the male.
- Brown upperparts
- Brownish-white underparts
- Very noticeable white rump
Juvenile similar to adult female in Hen Harrier; distinctly orange-toned in Northern Harrier.
In flight will show five obvious primaries (fingers) unless in moult.
Variation
The North American form has rufous-spotted flanks and thighs in males (like Cinereous Harrier but less marked), and females have darker upperparts and more orange underparts than females of the Eurasian form.
Similar species
See Montagu's Harrier and Pallid Harrier which both show four noticeable primaries in flight. Also see other harriers depending on where the observation is done; in Europe, Western Marsh Harrier is heavier with broader wings.
Distribution
Widespread in the Northern Hemisphere. The two subspecies Hen Harrier C. c. cyaneus and Northern Harrier C. c. hudsonius occupy the Old and the New World respectively.
In Europe and Asia, Hen Harrier breeds widely between around 35°N and 65°N latitudes across the entire width of the landmass. In Europe the main breeding range is from central Sweden, Finland and the Baltic States, south to the Black Sea and east to the Urals. However, also breeds patchily in Ireland and northern Britain (nearly extinct), in north and central France and northern Spain, with smaller populations in the Netherlands, Denmark and central Norway, Germany, Poland and the Czech Republic. Recently bred for the first time for many years in Italy. The Asian range extends from the Urals to the Pacific coast, breeding in the Russian far east, on Kamchatka and Sakhalin, and northern and eastern China. It is a summer visitor in Scandinavia, Russia and northern China, but resident or partly so in western and central Europe. Widespread in winter from British Isles, France and Spain east to the Black and Caspian Seas. Small numbers winter in Morocco and Egypt and can be seen on the major migration routes but relatively few cross the Mediterranean. Recorded in some numbers at Falsterbo, peaking in early-mid October. Asian populations winter south to Japan, southern China south of the Yangtze, and northern India; a rare straggler to Taiwan.
In North America Northern Harrier breeds over most of Alaska except the far north and Canada south of the tree-line. Also breeds over much of the western and northern USA but absent from the south, south-east and most of central USA. Southernmost breeding limit is northern Baja California. Winters from southern Canada and throughout the USA, and from Mexico to Panama, rarely the Caribbean, Colombia and Venezuela. This form has occurred as a vagrant in the Azores, the Faroes and in Britain.
A vagrant north to Iceland and the Faroes and to several Middle Eastern countries.
Taxonomy
Subspecies
Two subspecies are listed here following the Clements[1] and Howard & Moore[7] taxonomies; these are split as two separate species by several other recent authorities in view of the distinct morphological and ecological differences between the two, and the discovery that Northern Harrier is genetically closer to the South American Cinereous Harrier than it is to Hen Harrier[2][3][4][5].
- C. c. cyaneus (Hen Harrier):
- C. c. hudsonius (Northern Harrier):
- North America; winters to northern South America
Conservation
Hen Harrier populations are secure in some areas, but in others, notably Great Britain, have suffered massive declines due to determined criminal persecution by game-shooting estates. Northern Harrier populations are secure.
Habitat
Breeds in marshes, grasslands and heathlands, sometimes in mountains, often in cultivated areas.
Behaviour
Flight
Like all harriers, hunts using a low, slow flight over the ground, with their wings held in a shallow "V", then plunge onto their prey.
Diet
Includes small mammals, birds, reptiles, insects, and carrion.
Breeding
They build a nest of sticks and grass on the ground in thick heather, grass or shrubs. The clutch consists of three to six eggs which are incubated by the female for 29 - 31 days, fledging after about a month later.
They take 2 - 3 years to mature, but may attempt breeding in their first year.
Vocalisation
Call: kek, kek, kek
<flashmp3>Circus cyaneus (song).mp3</flashmp3>
Listen in an external program
References
- Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2015. The eBird/Clements checklist of birds of the world: v2015, with updates to August 2015. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
- Gill, F and D Donsker (Eds). 2011. IOC World Bird Names (version 2.10). Available at http://www.worldbirdnames.org/.
- Simmons, R. E. (2000). Harriers of the World. OUP, Oxford, UK.
- Ferguson-Lees, J., & Christie, D. A. (2001). Raptors of the World. Houghton Mifflin Co., Boston, New York.
- Dobson, A. D. M., & Clarke, M. L. (2011). Inconsistency in the taxonomy of Hen and Northern Harriers: causes and consequences. British Birds 104:192-201.
- Collins Field Guide 5th Edition
- Dickinson EC and JV Remsen, eds. (2013). The Howard and Moore complete checklist of the birds of the world. 4th edition vol. 1. Aves Press, Eastbourne, UK.
- The Peregrine Fund
- Collins Pocket Guide to British Birds 1966
- Birdforum thread discussing the taxonomy of harriers
Recommended Citation
- BirdForum Opus contributors. (2024) Northern Harrier. In: BirdForum, the forum for wild birds and birding. Retrieved 18 April 2024 from https://www.birdforum.net/opus/Northern_Harrier
External Links
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