Linear measurements (mm) and mass (g) for Northern Hawk Owl in North America. Sample includes individuals from Alberta, Alaska, British Columbia, Labrador, Manitoba, Minnesota, Nova Scotia, Northwest Territories, Ontario, Quebec, Saskatchewan, and Yukon. Breeding status generally not known. Data from personal communications (see Acknowledgments), references cited in text, and PAD, JRD. Data given as mean ± SE (range, n).

MaleFemalePooled sample
Wing (mm) (1)222.7 ± 1.5 (213–245, 24)228.3 ± 1.4 (210–242, 29)224.9 ± 0.4 (197–245, 321)
Tail (mm) (2)171.3 ± 2.2 (138–190, 28)173.8 ± 1.9 (156–191, 25)175.7 ± 0.6 (136–197, 257)
Total length (mm) (3)365.1 ± 8.4 (277–444, 17)374.7 ± 3.7 (310–398, 24)366.5 ± 4.7 (265–440, 47)
Bill (mm) (4)18.0 ± 0.3 (17.4–19.4, 6)19.5 ± 0.2 (18.6–20.0, 5)18.9 ± 0.3 (17.4–20.0, 5)
Foot (mm) (5)45.5 ± 0.1 (41–50, 168)
Ovaries (mm)9.3 ± 1.0 (5–12, 6)
Testes (mm)6.6 ± 1.0 (3.0–12.5, 12)
Mass (g)301.2 ± 4.8 (242–375, 42)339.8 ± 5.6 (250–454, 54)346.4 ± 2.5 (144.7–454.0, 339)