Some Special Owl Features
The wing feathers of an owl have a stiff leading edge and are softly fringed on the trailing edge. These traits affect the way air flows over the wing, and prevent the whistling sounds made by other birds in flight. Owl wing feathers can also slide soundlessly over one another due to their velvet-like surfaces.
An owl’s flight is silent not only to human ears, but even to the ultra-sensitive hearing of small animals. Owls can use their own keen hearing to zero in on an unsuspecting "meal" that never hears them coming.
The feathered facial disks that surround an owl’s eyes also cover hidden ear openings. The dish shape acts like a parabolic reflector, amplifying sounds. By turning and tipping its head, an owl can focus these reflectors to precisely locate prey.
Owls hear higher frequency sounds than humans by detecting a 10-150 millionths of a second difference in the time it takes the sound to reach each of their ear openings. Owls that hunt primarily by sound have asymmetrical ear openings that allow them to pinpoint faint sounds.
Owl eyes are extremely large for their body size. If we had eyes proportional to those of the Great Horned Owl, they would be the size of grapefruit and weigh 2-3 pounds each! Owl eyes face forward and are immovable, providing great binocular vision. Owls compensate for immovable eyes by the ability to rotate their heads about 270 degrees. Contrary to popular belief, owls have excellent vision both in daylight and at night. They can see in near darkness with large pupils that let them discern objects at one-tenth to one-hundredth the amount of light that we need.
Owl Pellets (Castings)
Owls and other raptors can’t chew their food so they either swallow it whole or tear it into pieces before swallowing. Undigested material is collected in the gizzard while the softer digestible material passes through. After several hours an owl will regurgitate, or cast, the undigested material in the form of a pellet. In addition to bones and hair, it is possible to find entire skulls of small mammals and birds in these pellets. Pellets are usually found under limbs of trees used by owls as a roost while digesting their meals.
An owl can grip with either three toes in front and one behind, or with two toes forward and two behind. This versatility combined with their long, sharp talons gives owls a powerful, sure grasp. Owls catch their prey with their talons but use a twist of their sharp, hooked bill to deliver the fatal blow.