I’ve always loved the cool, crisp nights of autumn. The sky looks darker, the stars brighter. In general, autumn nights are quieter. The constant chirping of summer insects has been silenced by dropping temperatures. If you’re lucky, though, your autumn nights may be punctuated by the eerie calls of owls.
Owls have always been victims of ignorance and superstition. Because of their nocturnal nature, owls have been perceived as ill omens or messengers of misfortune and even death. Despite this reputation, owls are particularly valuable as rodent predators, making them economically valuable in many areas. A single barn owl can eat more than a thousand mice a year!
Owls are silent hunters, aided by wings that have downy fringes, as well as stiff flight feathers, which muffle sound as they approach their prey.
The owl’s acute sense of hearing — most likely the best of any bird, and possibly any animal — also make it a formidable hunter. An owl can hear sounds 10 times fainter than the human ear can even detect.
Several features of an owl’s ear make it so sensitive. Its extra large ear openings, surrounded by deep, soft feathers, help to funnel sound. Also, the feathers over the ear, or auriculars, have no barbules, the parts of the feather that zip together to make it wind resistant, making the owl’s feathers loose and airy. A movable flap of skin, controlled by muscles around the ear opening, protects the ear and concentrates sound waves coming from behind.
Many owls also have asymmetrical ear openings. The opening in one ear will be higher than in the other ear. A sound coming from above will sound slightly louder in the ear with the higher ear opening. This allows the owl to pinpoint its prey accurately. Finally, the owl's entire face acts as an outer ear. The face is shaped like two parabolic curves or satellite dishes that funnels sound to the ears. The facial feathers are also compact and tight to aid in the funneling process.
Although some owls have ear tufts — feathers sticking up on the top of both sides of the head —they do nothing to improve hearing. Ear tufts make the owl appear larger, helping it to ward off predators.
Birds have relatively large eyes in relation to the size of the head. A human eye weighs less than 1 percent of the weight of the head. If people had eyes proportional to those of the great horned owl, our eyes would be the size of grapefruits and weigh five pounds! Owl eyes are so large that there is little room in their skulls for eye muscles. Thus, an owl turns its head, sometimes as much as 270 degrees, rather than its eyes, to follow a moving object.
It has been said that the difference between the hunter and the hunted is evident in the eyes. The hunted have eyes on the sides of their heads to obtain a wide field of view. Hunters have eyes on the front of their heads to increase depth perception. Owls have the most frontally positioned eyes of any animal.
Contrary to popular belief, owls have excellent vision in both daylight and at night. Their pupils are huge at night, letting in great quantities of light. Meanwhile, in the daytime, they shrink to the size of a pinpoint. This eyesight — which is 10 times as light-sensitive as human eyes — is the result of the concentration of light-sensitive rods in the retina. But it is at the expense of color defining cones, so,while owls see well in dim light, they see little color.
Owls have a few curious habits, too. Because they swallow their prey whole or nearly so, they must regurgitate pellets containing undigested parts of their prey — the bones, feathers or fur. They eject this matter in the form of a hard fur or feathered pellet, one per victim. By dissecting pellets, scientists can determine what animals make up the owl’s diet. When they eat insects, the pellet will contain the hard exoskeleton.
Owls do not build their own nests. Instead, they use old hawk or squirrel nests, natural cavities, buildings or constructed boxes. There are several species of owls that inhabit the Chesapeake Bay region during the winter or year round. Probably the most familiar of these is the great horned owl. This large, brown owl is noted by its large yellow eyes, white throat patch and large ear tufts. It can be recognized by its call: a series of low hoots: hoo-hoo hooo hoo-hoo.
Another “eared” owl, the long-eared owl, is similar in appearance to the great horned except that its ears tufts are closer together and it is smaller and slimmer.
The Eastern screech owl is a small (8 inches), eared owl with coloring that varies from rust to gray. Its call is a long, quivering whistle.
The barn owl is a light-colored, earless owl recognized by its heart-shaped face. As the name implies, the barn owl nests in barns, abandoned buildings and tree cavities. Its song is a long raspy screech.
Often referred to as the “hoot owl,” the barred owl’s call is made of 9 hoots that sound like the phrase Who-cooks-for-you, who-cooks-for-you-all?
The smallest of the Eastern owls, at 7 inches, is the northern saw-whet owl. It is often found roosting in dense evergreens or in thickets. Its call is a series of toots or whistles.
Owls have been the subject of much misunderstanding, superstition and fancy. Over the centuries, people have used owls to represent everything from evil and darkness to knowledge and wisdom. The wise, old owl is the most popular connotation today.
“A wise old owl sat on an oak
The more he saw the less he spoke
The less he spoke the more he heard
Why aren't we like that wise old bird?”
— Edward Hersey Richards