Avian Osteology

Species - Proximal End	mm	Species - Distal End	mm

Flammulated Owl	3 - 5	Flammulated Owl	4 - 5
Northern Pygmy-Owl	4 - 6	Northern Pygmy-Owl	4 - 6
Northern Saw-whet Owl	4 - 7	Sharp-shinned Hawk	5 - 7
American Kestrel	5 - 7	American Kestrel	5 - 7
Boreal Owl	5 - 7	Northern Saw-whet Owl	5 - 7
Sharp-shinned Hawk	5 - 8	Merlin	6 - 8
Merlin	6 - 8	Boreal Owl	6 - 9
Western Screech-Owl	6 - 8	Western Screech-Owl	7 - 8
Eastern Screech-Owl	6 - 8	Eastern Screech-Owl	7 - 9
Burrowing Owl	6 - 8	Burrowing Owl	7 - 9
Long-eared Owl	7 - 10	Copper's Hawk	8 - 11
Copper's Hawk	7 - 11	Northern Harrier	8 - 12
Northern Hawk Owl	8 - 10	Northern Hawk Owl	9 - 11
Short-eared Owl	8 - 10	Long-eared Owl	9 - 11
Northern Harrier	8 - 11	Short-eared Owl	9 - 12
Barn Owl	9 - 13	Barn Owl	10 - 15
Barred Owl	10 - 14	Peregrine Falcon	11 - 16
Prairie Falcon	10 - 15	Prairie Falcon	11 - 16
Peregrine Falcon	10 - 16	Northern Goshawk	12 - 16
Swainson's Hawk	11 - 14	Swainson's Hawk	12 - 16
Rough-legged Hawk	11 - 14	Rough-legged Hawk	12 - 16
Northern Goshawk	11 - 15	Barred Owl	12 - 16
Great Gray Owl	12 - 16	Osprey	14 - 17
Osprey	13 - 16	Red-tailed Hawk	14 - 17
Red-tailed Hawk	13 - 17	Great Gray Owl	14 - 18
Great Horned Owl	13 - 17	Gyrfalcon	15 - 19
Ferruginous Hawk	14 - 18	Ferruginous Hawk	15 - 20
Snowy Owl	14 - 18	Great Horned Owl	15 - 20
Gyrfalcon	15 - 18	Snowy Owl	15 - 20
Spotted Owl	16 - 18	Spotted Owl	16 - 19
Bald Eagle	19 - 24	Bald Eagle	22 - 29
Golden Eagle	20 - 25	Golden Eagle	22 - 29