Cooper's Hawk

Accipiter cooperii

Order:
Accipitriformes
Family:
Accipitridae
Sections

Tables and Appendices

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Table 1

Numbers of individual Cooper’s Hawks sighted at Cape May, NJ (a coastal site) and Hawk Mountain, PA (inland, ridge site), Hawk Ridge Bird Observatory, MN (inland, diversion line site), and Goshute Mountains, NV (inland, ridge site) 1980-2004. Counts reported are the middle 95% of birds passing each season. Unpublished data courtesy of Cape May Bird Observatory, Hawk Mountain Sanctuary, F. J. Nicoletti (Hawk Ridge Bird Observatory), and Jeff Smith (HawkWatch International).

YearGoshute MtnsHawk RidgeHawk MtnCape May
19801173701610
1981607542077
1982433001207
1983187566352744
19841486911701797
19851817682882663
19861179895661857
19872225665882928
19883046914582515
198931101447862000
19903617936421584
199128951555782116
199252671756561082
199323133195602450
199456271725673254
199529801036424994
199650841575254719
199736401857234911
1998659617311153037
199940422599333644
200029142277462611
200149551718971866
200223981375933499
200323311176814246
200428411335304890
Mean 3284 136 601 2732


Table 2

Proportions of avian and mammalian prey in studies using direct observations of nest deliveries or crop contents or prey remains. Note that only the first two listed studies show a minority of birds as prey.

State/Province

No.

Nests

No.

Items

Percent

Birds

Percent Mammals

Source

California

1

381

26

5

Fitch et al. 1946

Maryland

na2

57

30

70

Janik and Mosher 1982

Arizona-New Mexico

11

473

56

30

Snyder et al. 1973

New Mexico

17

1673

60

37

Kennedy 1991

Wisconsin

5

329

61

39

Bielefeldt et al. 1992

North Dakota

2

74

70

30

Peterson and Murphy 1992

Wisconsin

3

24

71

29

Errington 1933

Michigan

4

262

84

16

Hamerstrom and Hamerstrom 1951

Washington

6

240

90

10

Kennedy 1980

Florida

954

1,100

88

4

Millsap et al. 2013

British Columbia

1335

4,451

96

3

Cava et al. 2012

Arizona6

36

228

90

2

Estes and Mannan 2003

1 69% reptilian.

2 Not available.

3 3% reptilian.

4 10 nests with direct observation, 85 with prey remains; 4% mammal, rest reptilian and unknown.

5 87 nests with direct observation, (2 with videos), 44 nests with prey remains.

6 8% reptilian; only direct observations.

Table 3

Measures of reproductive success (sample sizes in parentheses).

  • (1)Active nests defined as those in which eggs were laid.
  • (2)na = not available.
  • (3)Number of bandable young aged ≥ 14 days.
  • Sources:  Craighead et al. 1969(MI),  ​Rosenfield and Anderson 2016(WI),  Reynolds and Wight 1978 (OR),  Hennessey 1978(UT),  Millsap 1981 (AZ),  Asay 1987 (CA),  Conrads 1990(IA).

State Hatching success (%) Nest success (%) Mean no. of Fledglings per active nest(1) Mean no. of Fledglings per successful nest
Michigan 74 (54) na(2) 2.8 (13) na
Wisconsin 95 (113) 69 (83) 2.4 (83)(3) 3.6 (48)(3)
Oregon 74 (50) 69 (29) 2.1 (24) 2.9 (na)
Utah na 53 (43) 1.6 (43) 2.9 (23)
Arizona 88 (na) 85 (46) 2.6 (46) 3.1 (34)
California 77 (221) 85 (55) 2.3 (55) 2.7 (47)
Iowa na 69 (29) 2.1 (29) 3.0 (20)


Appendix 1

Proportion of various clutch sizes from selected studies in North America. BC = British Columbia (Campbell et al. 1990); ON = Ontario (Peck and James 1983); WI = Wisconsin, 1980–1982 (Rosenfield and Anderson 2016); NE = northeastern U. S. and se. Canada (Henny and Wight 1972; includes data from Meng 1951).

  • (1)Includes Meng (Meng 1951

Mean Clutch Sizes
Size (n) Years Location Source
4.0 (7) 1947–1978 Michigan
4.2 (117) 1880–1967 NE U.S. and SE Canada (1)
3.8 (13) 1969–1974 Oregon
3.6 (8) 1979–1980 Maryland Janik and Mosher 1980
3.3 (46) 1980–1981 Arizona
4.4 (39) 1980–1982 Wisconsin
3.6 (52) NA Ontario
4.0 (55) 1977–1980 California
3.7 (33) NA British Columbia
Number of eggs per clutch BC WI ON NE
1 0 0 2 0
2 9 0 6 0
3 27 18 42 18
4 48 32 31 48
5 16 50 17 32
6 0 0 0 2
7 0 0 2 0
No. of nests studied 33 38 52 117


Appendix 2

Geographic, sexual, and age variation in linear measurements (mm) and mass (g) of autumn migrants and breeding birds. Mean ± SD (n) for all studies except Mean ± SE (n) for Wisconsin breeders.

  • (1)Nonbreeding summer birds.
  • Sources: West,Hoffman et al. 1990b(Nevada migrants),Henny et al. 1985c(Oregon breeders). East,Mueller et al. 1981b(Wisconsin migrants),​Rosenfield et al. 2010(Wisconsin breeders at least 2 years of age).

  West East
  Migrant Breeding Migrant Breeding
Wing (unflattened) (mm)
Basic Male 225 ± 5 (287) 224 ± 5 (41) 238 ± 5 (48) 237 ± 1 (68)
Basic Female 256 ± 6 (545) 254 ± 7 (24) 270 ± 7 (56) 267 ± 1 (58)
Juv. Male 224 ± 5 (317) 234 ± 4 (52)
Juv. Female 254 ± 6 (444) 266 ± 5 (59)
Tail (mm)
Basic Male 181 ± 7 (128) 179 ± 4 (37) 191 ± 5 (51) 185 ± 1 (68)
Basic Female 209 ± 7 (285) 207 ± 7 (23) 221 ± 7 (58) 210 ± 1 (58)
Juv. Male 190 ± 6 (194) 196 ± 5 (52)
Juv. Female 214 ± 7 (286) 221 ± 7 (58)
Mass (g)
Basic Male 281 ± 19 (177) 280 ± 19 (48) 349 ± 20 (51) 327 ± 2 (69)
Basic Female 439 ± 35 (416) 473 ± 41 (20) 529 ± 36 (57) 580 ± 5 (58)
Juv. Male 269 ± 22 (183) 276 ± 26 (9)(1)1 335 ± 26 (53)
Juv. Female 399 ± 36 (310) 486 ± 29 (5) 499 ± 40 (58)


Recommended Citation

Rosenfield, R. N., K. K. Madden, J. Bielefeldt, and O. E. Curtis (2019). Cooper's Hawk (Accipiter cooperii), version 3.0. In The Birds of North America (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.coohaw.03