Hen Harrier Circus cyaneus   [Linnaeus, 1766]

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Order: Accipitriformes Family: Accipitridae
BTO Codes: HH, HENHA EURING No: 2610
Number in Britain: 570 Pairs (Summer)
Conservation Status:
European: 3 Concern, most not in Europe; Depleted
Global: (Details)
Status in UK: (A)  Migrant/Resident Breeder, Passage/Winter Visitor
Subspecies: cyaneus, hudsonius recorded in Britain (of 2 subsp. in the world)
Length: 48 cm Wingspan: 110 cm Weight: M: 350 g   F: 500 g    
Scientific name from: Gr.: kirkos=a type of hawk and L.: cyaneus=dark-blue (from Gr.:kuanos)
World Distribution: BREEDS: Europe, n&c Asia, North America, WINTERS: south to n Africa, s Asia & n South America
Habitat: Moor, marsh, steppe and fields
Diet: Mostly, small birds, nestlings and small rodents
TitBit: The relationship between harrier and grouse and their keepers is a complex and contentious one, but harriers feed mainly on voles and pipits, which prefer grassland, good moor management for heather will exclude both the harrier and its prey.  
Identification Tips:
  Images from IBC or search flickr
  Videos from IBC
  Sound from xeno-canto
Crossley ID photos

Population and Distribution

Population Trend: BirdTrends   
Regional Trends: No regional trends available
Distribution: No distribution maps available
British Population Size:
    Summer: 570 Pairs in 2010
    First Record: 1544
    Latest Survey: Musgrove, A. et al. (2013) British Birds 106:64-100
    Conservation Status: RED because Historical Population Decline,
   Previous Assessments: 2002-2007 RED     1996-2001 RED  
   Races of Concern: cyaneus RED (Historical Decline)
Habitat Occupancy (in the Breeding Season):
    No habitat data from BBS
Migration routes: Map of foreign ringing recoveries
European Population Size:
    Summer: 12 to 19 thousand pairs
Population Assesment from Birds in Europe
Distribution in Europe mapped by the EBCC Atlas
Listed on the Appendices/Schedules of: WCA(I,IV), WBD(I), Bern(III), Bonn(II), CITES(II), NERC (41)
Survey Results:

Breeding and Survival

Egg Size: 46 x 36 mm Egg Weight: 31.0 g (of which 8 % is shell)
Number of Nest Records: 50   (more would be welcome!)
Clutch Size: 4 - 5 eggs 4.63 1.07 (2 - 8) N = 370
Incubation: 34 days 33.77 2.42 (29 - 39.5) N = 370   by the: Female
Fledging: 37 - 42days 38.68 3.96 (31 - 46) N = 578 as: Altricial, downy
British Trust for Ornithology (2005) Nest Record Scheme data
First Clutches Laid: Unavailable
Number of Broods: 1
See trends in Breeding Productivity
Number Ringed: Annual Totals
Adult Survival: 0.810    (M:0.720 0.070; F:0.900 0.030)      
Juvenile Survival: 0.220 (to age 2 )  
Age at First Breeding: 2 years Typical Lifespan: 7 years
Maximum Recorded Age: 15 years 9 months 2 days (set in 1990)
Read a summary of Ringing Recoveries


Ring Size: E or F
Wing Length Adult: Insufficient Data
Juvenile: Insufficient Data
Male: Insufficient Data
Female: Insufficient Data
Weight Adult: Insufficient Data
Juvenile: Insufficient Data
Male: Insufficient Data
Female: Insufficient Data

Other Names

Northern Harrier
Gaelic: Clamhan-nan-cearc Welsh: Bod Tinwen
Danish: Bl krhg Dutch: Blauwe kiekendief
Finnish: Sinisuohaukka French: Busard Saint-Martin
German: Kornweihe Hungarian: Kkes rtihja
Icelandic: Blheiir Irish: Cromn na Cearc
Italian: Albanella reale Norwegian: Myrhauk
Polish: Blotniak zbozowy Portuguese: Tartaranho-azulado
Spanish: Aguilucho plido Swedish: Bl krrhk
Local Names: Ringtail (f), Miller

For More Information...

Books and Monographs:
   Simmons, R. 2000 Harriers of the world : their behaviour and ecology Oxford University Press, Oxford [598.521 SIM]
   Clarke, R. 1990 Harriers of the British Isles Shire Publications, Princes Risborough [Jour: S]
See Also:
Find scientific papers on Google Scholar or Scirus by clicking the icon
Wikipedia entry
HBW account (subscription required)
BirdLife species page
Recent sightings and information from BirdGuides
All About Birds (from the Cornell Lab of Ornithology)