Northern Harrier

Circus hudsonius

General Status Rank: 
Secure
ELCODE: 
ABNKC11010
Common Name: 
Northern Harrier
Scientific Name: 
Circus hudsonius
Synonyms: 
Circus cyaneus hudsonius
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Taxonomy
Group: 
Bird
Kingdom: 
Animalia
Phylum: 
Chordata
Class: 
Aves
Order: 
Accipitriformes
Family: 
Accipitridae
References: 
ASC13
General Biology

Female Age at Maturity

1 year(R016); 16% of 268 breeding females were yearlings, and in New Brunswick, 23% of 116 of females were subadults (≤2 yr)( B130)
References: 
R078
B130

Longevity

up to 16 years (R078); Among 114 banded birds, mean age at death 16.6 mo (Keran 1981). Longest lifespan reported: 16 yr 5 mo (Bildstein 1988). Greatest reported known age of (female) breeding bird in North America: 8 yr (RBM) (B130).
References: 
R078
B130

Economic/Human Considerations

useful to agriculture because kills rodents
References: 
R078
Habitat
open, often wet areas (meadows, marshes, fields, bogs, even agricultural lands)
References: 
B004
R078
Distribution

Ecozones

Southern Arctic, Taiga Cordillera, Taiga Plains, Taiga Shield, Boreal Cordillera, Boreal Plains
References: 
B004

Distribution

0.60, Fairly common migrant and breeder in open areas and wetlands throughout the mainland and up to the North Coast. (NWT Bird checklist project)
Score: 
G
References: 
R078
Winter Distribution Description: 
Alaska and southern Canada to South America

Number of Occurrences

unknown; assumed at least 100 nests Early record: 25 March 2002; 1 individual; Mackenzie Delta; Karsten Heuer; eBird 2012. Late record: 17 October 1999; 1 individual; Fort Simpson; Doug Tate; eBird 2012. High count: 10 individuals; 11 June 2002; Fort Resolution; Paul Jones eBird 2012.(NWT Bird checklist project)
Score: 
DE
References: 
H126

Area of Occupancy

Assumed stable; variable due to prey base variation (small mammals)
Score: 
-
References: 
H126
R078
W027
B130
Population

Population Size

uncommon; numbers unknown; Assumed more than 3000 because of large distribution base (R078);Species is nomadic; densities in breeding and nonbreeding seasons vary in response to local changes in prey availability (B130)
Score: 
E
References: 
H126
R078
B130
Trends

Trends

Small cyclic fluctuations coinciding with vole popns; may be assumed stable in NWT; In Canada, BBS data suggest long-term significant increases in western mountain provinces, with declines in the prairies, particularly during 1982–1991; elsewhere, numbers stable (Kirk et al. 1995).(B130)BBS 1967-2000 (Canada): -4.6 (-6.3 to -2.9), P <0.05, N=282 routes, BBS 1966-2000 (North America): -0.7 (-1.6 to 0.2), P =0.15, N=966 routes, CBC 1959-1988 (North America): -0.4 (-1.3 to 0.6), NS, N=1712 counts (W027)
References: 
H126
R078
W027
B130
Threats

Threats

In South habitat loss, pesticide contamination, human persecution; limited in NWT
References: 
H126
R078

Intrinsic Vulnerability

Elsewhere in Canada and on migratory route reforestation efforts, intensive agriculture, urbanization, wetland drainage; limited habitat threats in NWT
Score: 
C
References: 
H126
R078
General Status Rank
Rank: 
Secure
Status Rank Description: 
But unknown number of pairs, nesting sites, trend in population can only be inferred from BBS in the south (some decline).
S Rank: 
S4?
Decision Process Description: 
Drafted by Suzanne Carriere based on printed references. Reviewed in 2005 by S Carrière based on printed literature only :no change in rank; Reviewed in 2010;no change; Reviewed in 2015, no change; Reviewed in 2020, no change
Last Updated: 
June 18, 2020
Status Designations

Canada – Assessment by Committee on the Status of Endangered Wildlife in Canada

References: 
R078

References

Age Of Maturity

  • Cadman MD (1993) Status report on the northern harrier Circus cyaneus in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R078 Return
  • MacWhirter, R. B., and K. L. Bildstein. (1996) Northern Harrier (Circus cyaneus). In The Birds of North America,. No. 210 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The Ornithologists’ Union, Washington, D.C. http://bna.birds.cornell.edu/ - B130 Return

Area of Occupancy

  • Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return
  • Cadman MD (1993) Status report on the northern harrier Circus cyaneus in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R078 Return
  • Dunn, E.H (2005) National action needs for Canadian Landbird Conservation,. Canadian Wildlife Service Landbird Committee, Version 1. [http://www.cws-scf.ec.gc.ca/birds/action/index_e.cfm]. - W027 Return
  • MacWhirter, R. B., and K. L. Bildstein. (1996) Northern Harrier (Circus cyaneus). In The Birds of North America,. No. 210 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The Ornithologists’ Union, Washington, D.C. http://bna.birds.cornell.edu/ - B130 Return
COSEWIC Status
  • Cadman MD (1993) Status report on the northern harrier Circus cyaneus in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R078 Return

Economic Status

  • Cadman MD (1993) Status report on the northern harrier Circus cyaneus in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R078 Return

Ecozones

  • Godfrey WE (1986) The Birds of Canada. National Museums of Canada Revised Edition RWED Library Call #QL685.G6 - B004 Return

Habitat

  • Godfrey WE (1986) The Birds of Canada. National Museums of Canada Revised Edition RWED Library Call #QL685.G6 - B004 Return
  • Cadman MD (1993) Status report on the northern harrier Circus cyaneus in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R078 Return

Intrinsic Vulnerability

  • Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return
  • Cadman MD (1993) Status report on the northern harrier Circus cyaneus in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R078 Return

Longevity

  • Cadman MD (1993) Status report on the northern harrier Circus cyaneus in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R078 Return
  • MacWhirter, R. B., and K. L. Bildstein. (1996) Northern Harrier (Circus cyaneus). In The Birds of North America,. No. 210 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The Ornithologists’ Union, Washington, D.C. http://bna.birds.cornell.edu/ - B130 Return

NWT Known Subspecies

Godfrey WE (1986) The Birds of Canada. National Museums of Canada Revised Edition RWED Library Call #QL685.G6 - B004 Return

Number of Occurrences

  • Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return

Population Size

Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return
,
Cadman MD (1993) Status report on the northern harrier Circus cyaneus in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R078 Return
,
MacWhirter, R. B., and K. L. Bildstein. (1996) Northern Harrier (Circus cyaneus). In The Birds of North America,. No. 210 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The Ornithologists’ Union, Washington, D.C. http://bna.birds.cornell.edu/ - B130 Return

Range Extent

  • Cadman MD (1993) Status report on the northern harrier Circus cyaneus in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R078 Return

Short Term Trends

  • Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return
  • Cadman MD (1993) Status report on the northern harrier Circus cyaneus in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R078 Return
  • Dunn, E.H (2005) National action needs for Canadian Landbird Conservation,. Canadian Wildlife Service Landbird Committee, Version 1. [http://www.cws-scf.ec.gc.ca/birds/action/index_e.cfm]. - W027 Return
  • MacWhirter, R. B., and K. L. Bildstein. (1996) Northern Harrier (Circus cyaneus). In The Birds of North America,. No. 210 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The Ornithologists’ Union, Washington, D.C. http://bna.birds.cornell.edu/ - B130 Return

Taxonomy

  • Chesser, R. Terry, Richard C. Banks, F. Keith Barker, Carla Cicero, Jon L. Dunn, Andrew W. Kratter, Irby J. Lovette, Pamela C. Rasmussen, J. V. Remsen, James D. Rising, Douglas F. Stotz, Kevin Winker. (2010) Fifty-first supplement to the American Ornithologists' Union Check-List of North American Birds.. Auk 127(3):726-744. - ASC13 Return

Threats

  • Carrière, S. (2000) Pers. communication. Ecosystem Management Biologist; RWED - H126 Return
  • Cadman MD (1993) Status report on the northern harrier Circus cyaneus in Canada. Committee on the Status of Endangered Wildlife in Canada (COSEWIC) RWED Library Folder - R078 Return