Avian Osteology

Species - Proximal End	mm	Species - Distal End	mm

Flammulated Owl	4 - 5	Flammulated Owl	1 - 3
Northern Pygmy-Owl	4 - 6	Northern Pygmy-Owl	1 - 3
American Kestrel	5 - 7	American Kestrel	4 - 6
Northern Saw-whet Owl	5 - 7	Sharp-shinned Hawk	5 - 7
Boreal Owl	5 - 8	Northern Saw-whet Owl	5 - 7
Western Screech-Owl	6 - 8	Boreal Owl	5 - 8
Eastern Screech-Owl	6 - 8	Merlin	6 - 8
Burrowing Owl	6 - 8	Western Screech-Owl	6 - 8
Merlin	6 - 9	Eastern Screech-Owl	6 - 8
Sharp-shinned Hawk	7 - 8	Burrowing Owl	6 - 8
Short-eared Owl	7 - 11	Copper's Hawk	7 - 10
Long-eared Owl	8 -10	Long-eared Owl	7 - 10
Copper's Hawk	9 - 10	Northern Hawk Owl	8 - 10
Northern Hawk Owl	9 -11	Northern Harrier	8 - 11
Northern Harrier	9 - 13	Short-eared Owl	8 - 11
Barn Owl	9 - 13	Barn Owl	9 - 13
Prairie Falcon	9 - 15	Peregrine Falcon	13 - 19
Peregrine Falcon	10 - 15	Prairie Falcon	14 - 17
Spotted Owl	11 - 14	Great Horned Owl	15 - 20
Swainson's Hawk	11 - 16	Spotted Owl	16 - 19
Barred Owl	12 - 15	Barred Owl	16 - 19
Osprey	12 - 19	Swainson's Hawk	17 - 21
Rough-legged Hawk	13 - 17	Red-tailed Hawk	17 - 21
Red-tailed Hawk	13 - 18	Northern Goshawk	17 - 23
Great Gray Owl	14 - 18	Rough-legged Hawk	17 - 24
Northern Goshawk	15 - 16	Gyrfalcon	18 - 21
Great Horned Owl	15 - 17	Ferruginous Hawk	20 - 24
Gyrfalcon	15 - 19	Great Gray Owl	20 - 24
Snowy Owl	15 - 19	Osprey	21 - 25
Ferruginous Hawk	16 - 21	Snowy Owl	22 - 27
Bald Eagle	23 - 29	Bald Eagle	30 - 38
Golden Eagle	24 - 30	Golden Eagle	32 - 39