Owls of Ohio - Ohio Department of Natural Resources
Owls of Ohio - Ohio Department of Natural Resources Owls of Ohio - Ohio Department of Natural Resources
Owl Morphologyowls of ohioO W L S O F O H I OE xcep ti o nal H e aring owl morphologyMost birds have great hearing; in owls, this senseis truly exceptional, much better than is the case inhumans. The “ear tufts” that many species display arenot ears at all; rather they are probably just for displaypurposes. The actual ear opening, known as an aperture,is hidden under the feathers on each side of the head. Insome species, each aperture is offset, or asymmetrical,which better helps the owl triangulate on the location ofa sound. Owls can more or less instantly tell if a soundhas come from the right or left. Studies have shown thatthe brains of some species of owls can process a right/leftdifference in the arrival of a sound of only 30 millionthsof a second. These highly developed audio abilities allowowls to even catch prey that is hidden under snow!S pecialized Vision owl morphologyOwls have highly specialized vision, not only to allowthem to navigate at night – most are nocturnal – but alsoto accommodate their highly predatorial habits. Owl eyesare enormous, and in some species may encompass up tofive percent of the bird’s overall mass. This allows them tomore efficiently collect and process light in dim conditions,thus allowing them to visually locate prey under darkconditions. Owl’s eyes face directly forward, providingthem with binocular vision, meaning they see an objectNorthern saw-whet owl,showing ear aperturePhoto by: ODNR Division of Wildlife / Jim McCormac
with both eyes simultaneously. Another adaptation isthe ability to swivel their heads about 270 degrees, andthus look directly behind them without moving theirbody. Fourteen neck vertebrae allow this exceptionalflexibility; for comparison, humans have only sevenvertebrae in the neck.P ower fu l Talo n s an d B i ll owl morphologyAs befits predators near the top of the food chain, owlshave very powerful talons that allow them to forcefullyseize prey. In many species, the legs and feet are fullyfeathered. This is probably primarily an adaptation forcold weather, but these feathers may also help them to“feel” their prey and make rapid adjustments if need be.Each foot has four talons; three face forward and onebackwards, creating an exceptionally effective snare.While humans must keep their muscles contractedwhen holding an object, owls have what is essentiallya mechanical locking device that allows them to graspan object with full force without constant musclecontractions. Their bills are also powerful and hooked,and the owl can exert great force with it. Smaller preyare often quickly dispatched with crushing pressureusing the bill.D i g e s ti o n owl morphologyOwls, like all other birds, cannot chew their food.Thus, smaller prey is swallowed whole, and largerprey is ripped into manageable pieces which can thenbe swallowed. The problem with this system is thatindigestible parts of the animal are also consumed.To effectively rid their digestive tracts of indigestiblematerials such as bones and fur, owls regurgitate whatGreat horned owl talonsPhoto by: ©W. Greene / VIREO
- Page 1 and 2: OWLS OF OHIO c d g u i d e b o o kD
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- Page 7 and 8: M o d i fi ed Fe ath er s owl morph
- Page 9 and 10: Pelle t s an d W h ite wa s h findi
- Page 11 and 12: Ab o u t this Bookle t and CD owls
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- Page 15 and 16: y people placing nest boxes in barn
- Page 17 and 18: BTRACKS7-12arred owlStrix varia (St
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- Page 21 and 22: Eastern screech-owlMegascops asio (
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- Page 25 and 26: Great horned owlBubo virginianus (B
- Page 27 and 28: Normally solitary except during the
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- Page 31 and 32: O h i o S tat u s l o ng - e a re d
- Page 33 and 34: N e s ting long - e a re d o w lLon
- Page 35 and 36: Northern saw-whet owlAegolius acadi
- Page 37 and 38: likely. When one is found, a very c
- Page 39 and 40: Short-eared owlAsio flammeus (Ay-se
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- Page 43 and 44: C O M M O N O W L S O F O H I O 43i
- Page 45 and 46: C O M M O N O W L S O F O H I O 45O
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- Page 49 and 50: Like the Northern hawk owl and grea
- Page 51 and 52: This is one of North America’s mo
- Page 53 and 54: This is the smallest owl in the wor
with both eyes simultaneously. Another adaptation isthe ability to swivel their heads about 270 degrees, andthus look directly behind them without moving theirbody. Fourteen neck vertebrae allow this exceptionalflexibility; for comparison, humans have only sevenvertebrae in the neck.P ower fu l Talo n s an d B i ll owl morphologyAs befits predators near the top <strong>of</strong> the food chain, owlshave very powerful talons that allow them to forcefullyseize prey. In many species, the legs and feet are fullyfeathered. This is probably primarily an adaptation forcold weather, but these feathers may also help them to“feel” their prey and make rapid adjustments if need be.Each foot has four talons; three face forward and onebackwards, creating an exceptionally effective snare.While humans must keep their muscles contractedwhen holding an object, owls have what is essentiallya mechanical locking device that allows them to graspan object with full force without constant musclecontractions. Their bills are also powerful and hooked,and the owl can exert great force with it. Smaller preyare <strong>of</strong>ten quickly dispatched with crushing pressureusing the bill.D i g e s ti o n owl morphology<strong>Owls</strong>, like all other birds, cannot chew their food.Thus, smaller prey is swallowed whole, and largerprey is ripped into manageable pieces which can thenbe swallowed. The problem with this system is thatindigestible parts <strong>of</strong> the animal are also consumed.To effectively rid their digestive tracts <strong>of</strong> indigestiblematerials such as bones and fur, owls regurgitate whatGreat horned owl talonsPhoto by: ©W. Greene / VIREO
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