Avian Osteology

Species - Proximal End	mm	Species - Distal End	mm

Northern Pygmy-Owl	4 - 8	Northern Pygmy-Owl	5 - 7
Flammulated Owl	6 - 8	Flammulated Owl	6 - 7
Northern Saw-whet Owl	7 - 9	American Kestrel	6 - 8
Eastern Screech-Owl	8 - 11	Northern Saw-whet Owl	7 - 9
Boreal Owl	8 - 11	Burrowing Owl	8 - 10
American Kestrel	8 - 13	Boreal Owl	8 - 10
Western Screech-Owl	9 - 11	Merlin	8 - 11
Burrowing Owl	9 - 11	Eastern Screech-Owl	8 - 11
Sharp-shinned Hawk	9 - 14	Sharp-shinned Hawk	8 - 12
Merlin	10 - 18	Western Screech-Owl	9 - 11
Northern Hawk Owl	11 - 14	Copper's Hawk	10 - 15
Long-eared Owl	11 - 15	Northern Hawk Owl	11 - 14
Short-eared Owl	13 - 16	Long-eared Owl	11 - 14
Copper's Hawk	13 - 17	Short-eared Owl	13 - 15
Great Horned Owl	13 - 17	Northern Harrier	13 - 17
Barn Owl	14 - 18	Barn Owl	13 - 17
Northern Harrier	15 - 27	Peregrine Falcon	13 - 19
Prairie Falcon	15 - 28	Prairie Falcon	14 - 17
Spotted Owl	16 - 18	Great Horned Owl	15 - 20
Barred Owl	16 - 20	Spotted Owl	16 - 19
Peregrine Falcon	17 - 34	Barred Owl	16 - 19
Red-tailed Hawk	18 - 33	Swainson's Hawk	17 - 21
Northern Goshawk	19 - 23	Red-tailed Hawk	17 - 21
Swainson's Hawk	19 - 27	Northern Goshawk	17 - 23
Rough-legged Hawk	20 - 25	Rough-legged Hawk	17 - 24
Great Gray Owl	20 - 25	Gyrfalcon	18 - 21
Ferruginous Hawk	24 - 29	Ferruginous Hawk	20 - 24
Gyrfalcon	24 - 35	Great Gray Owl	20 - 24
Snowy Owl	25 - 29	Osprey	21 - 25
Osprey	25 - 40	Snowy Owl	22 - 27
Golden Eagle	34 - 42	Golden Eagle	30 - 38
Bald Eagle	36 - 43	Bald Eagle	32 - 39