Avian Osteology

Species - Proximal End	mm	Species - Distal End	mm

Northern Pygmy-Owl	3 - 5	Northern Pygmy-Owl	2 - 4
Flammulated Owl	4 - 5	Flammulated Owl	3 - 4
Northern Saw-whet Owl	4 - 6	Northern Saw-whet Owl	4 - 5
Western Screech-Owl	5 - 7	Sharp-shinned Hawk	4 - 6
Eastern Screech-Owl	5 - 7	Western Screech-Owl	4 - 6
Burrowing Owl	5 - 7	Burrowing Owl	4 - 6
Boreal Owl	5 - 7	Boreal Owl	4 - 6
American Kestrel	6 - 9	Eastern Screech-Owl	4 - 7
Sharp-shinned Hawk	6 - 10	American Kestrel	4 - 8
Northern Hawk Owl	7 - 9	Merlin	5 - 7
Long-eared Owl	7 - 10	Copper's Hawk	5 - 9
Merlin	8 - 10	Long-eared Owl	6 - 8
Copper's Hawk	8 - 11	Barn Owl	6 - 9
Short-eared Owl	8 - 11	Short-eared Owl	6 - 9
Barn Owl	9 - 12	Northern Hawk Owl	7 - 9
Prairie Falcon	9 - 16	Northern Harrier	7 - 11
Peregrine Falcon	9 - 18	Prairie Falcon	8 - 12
Spotted Owl	10 - 13	Barred Owl	8 - 12
Barred Owl	10 - 13	Peregrine Falcon	8 - 14
Northern Harrier	12 - 14	Swainson's Hawk	9 - 11
Great Gray Owl	12 - 15	Northern Goshawk	9 - 12
Great Horned Owl	12 - 15	Spotted Owl	9 - 12
Northern Goshawk	13 - 16	Red-tailed Hawk	9 - 13
Swainson's Hawk	13 - 16	Rough-legged Hawk	9 - 13
Snowy Owl	13 - 18	Great Horned Owl	10 - 13
Ferruginous Hawk	13 - 19	Gyrfalcon	10 - 14
Rough-legged Hawk	14 - 17	Ferruginous Hawk	11 - 14
Red-tailed Hawk	14 - 18	Snowy Owl	11 - 14
Gyrfalcon	14 - 19	Great Gray Owl	11 - 14
Osprey	15 - 20	Osprey	11 - 16
Golden Eagle	24 - 28	Golden Eagle	14 - 20
Bald Eagle	24 - 29	Bald Eagle	15 - 21